President Trump continued to insist on Monday that the tariff-averting border deal he reached with Mexico on Friday is more robust than critics and news reports suggest, tweeting: "We have fully signed and documented another very important part of the Immigration and security deal with Mexico, one that the U.S. has been asking about getting for many years. It will be revealed in the not too distant future and will need a vote by Mexico's legislative body!"

In a news conference in Mexico City on Monday, Mexican Foreign Minister Marcelo Ebrard said Mexico had not agreed to any secret immigration deal, also denying an earlier tweet in which Trump said Mexico had agreed to buy more U.S. agricultural goods.

Instead, Ebrard said, Mexico agreed that if the flow of migrants to the U.S. did not drop significantly in coming months, both sides would meet again to discuss more aggressive changes to regional asylum rules. "Let's have a deadline to see if what we have works, and if not, then we will sit down and look at the measures you propose and those that we propose," he said. U.S. officials tell The New York Times that Trump's tweet appeared to refer to an agreement in the published deal to revisit the migration situation with Mexico in 45 and 90 days.

In last week's negotiations, the U.S. team had pressed Mexico to enact a "safe third country" system in which migrants fleeing Central America would have to apply for asylum in Mexico, and the U.S. could turn away those who didn't. Mexico refused. "There appeared to be a significant disagreement on Monday between the Mexican government and American officials about what the negotiators actually agreed to regarding further action and the possibility of implementing a 'safe third country' arrangement," the Times reports. U.S. officials said Mexico all but agreed to a regional system that would mimic a "safe third country" law, while Ebrard said the deal effectively put off that discussion. Peter Weber

Badlands National Park in South Dakota has expanded its bison range, a move that will "contribute to the health and genetic integrity of the herd and continued health of the prairie," the park said.

The bison now have an additional 22,000 acres of grazing land, for a total of 80,193 acres. The park itself is 244,000 acres, with about 1,200 bison calling it home. On Friday, four bison were moved to the new range, returning to the area for the first time in 150 years.

New fencing and cattle guards were installed in the range, thanks to $743,000 in public and private donations. Due to the expansion, visitors will have "more opportunities for viewing, photographing, and learning about bison in their native habitat on the badlands' iconic and stunning landscape," the park said. Former President Barack Obama named the bison the national mammal in 2016. Catherine Garcia

Moving up from the south, Syrian government troops seized several towns in the northeastern part of the country on Monday, one day after reaching an agreement with the Kurdish-led militia that has held control of the area for several years.

The Kurds and Syria reached the deal after President Trump pulled back U.S. troops from the border, giving Turkey the opportunity to invade Syria and launch an assault on the Kurds. The Kurds and United States worked together to fight the Islamic State in Syria, and the Kurds took control over territory lost by ISIS. After the U.S. retreat, the Kurds turned to the Syrian government for added protection against Turkey. Turkish President Recep Tayyip Erdogan considers the Kurds terrorists.

Syrian government forces were able to take control of multiple towns from the Kurds, including Taqba, which has a hydroelectric dam on the Euphrates. Kurdish fighters spent Monday battling Turkish troops and allied Syrian militias in the border towns of Ras al Ain and Tal Abyad. The recent developments are viewed as victories for Syrian President Bashar al-Assad, who counts Russia and Iran as his allies.

Complicating matters is the fact that the U.S. has about 50 tactical nuclear weapons stored at the Incirlik Air Base in Turkey, 250 miles from the Syrian border. Two U.S. officials told The New York Times that over the weekend, State and Energy Department employees were reviewing plans for getting the weapons out of Turkey. They are "essentially Erdogan's hostages," the Times says, and moving them from Turkey would basically end the alliance between the United States and Turkey. Leaving them is just as problematic, as it puts the weapons and U.S. in a vulnerable position. Read more at The New York Times. Catherine Garcia

Former National Security Adviser John Bolton was so alarmed by a White House–linked effort to pressure Ukraine to investigate Democrats, he told aide Fiona Hill to alert the National Security Council's chief lawyer, Hill told House impeachment investigators in her 10-hour deposition on Monday, The New York Times and The Wall Street Journal report. Specifically, Bolton told Hill, the top NSC staffer on Russia and Eurasian affairs, to notify White House lawyers that Rudy Giuliani, White House acting Chief of Staff Mick Mulvaney, and U.S. Ambassador Gordon Sondland were running a rogue operation, the Times reports.

"I am not part of whatever drug deal Sondland and Mulvaney are cooking up," Bolton reportedly told Hill to relate to the lawyers, after a heated July 10 meeting with Sondland, the U.S. ambassador to the European Union and a key player in the Ukraine pressure campaign, and Ukrainian officals. Before that meeting, Hill reportedly testified, Bolton told her that "Giuliani's a hand grenade who's going to blow everybody up." Giuliani, President Trump's personal lawyer, is now under federal criminal investigation for his work in Ukraine, the Journal reported Monday. Sondland is scheduled to be deposed on Thursday.

House investigators are now trying to decide whether to question Bolton, The Washington Post reports.

Hill also testified that he had strongly opposed Giuliani's successful push to have Trump remove America's ambassador to Kyiv, Marie Yovanovitch, who had a reputation for fighting corruption in Ukraine. "I don't know Fiona and can't figure out what she is talking about," Giuliani told the Post on Monday night, adding that he believes she was out of the loop when it came to Ukraine, at least compared with Sondland. "She just didn't know," Giuliani said, reiterating his assertion that he was working on orders from the State Department. Peter Weber

Update, 12:47 a.m.: This article has been updated based on a clarification by the Times:

A Fort Worth, Texas, police officer who shot and killed a woman inside her home early Saturday was charged with murder on Monday, shortly after he resigned from the force.

The former officer, Aaron Dean, is being held at the Tarrant County Correction Center, Fort Worth Police Sgt. Chris Daniels said. The woman, 28-year-old Atatiana Jefferson, was playing video games with her 8-year-old nephew when she was shot. A neighbor had noticed Jefferson's front door was slightly open and called the police department's non-emergency line, asking them to do a wellness check. Body-camera footage released by the police department shows an officer shining a flashlight into the house, then yelling, "Put your hands up, show me your hands," before firing one shot.

The white officer shooting a black woman inside her home caused immediate outrage in Fort Worth, and Daniels had a message for all concerned. "To the citizens and residents of our city, we feel and understand your anger and your disappointment and we stand by you as we work together to make Fort Worth a better place for us all," he said. Jefferson's older sister, Ashley Carr, said Atatiana was "simply going on along with her life, living a law-abiding citizen's peaceful life, and she was killed by a reckless act of a Fort Worth police officer. There is simply no justification for his actions." Catherine Garcia

During her testimony before House lawmakers on Monday, Fiona Hill, President Trump's former top Russia adviser, said that Rudy Giuliani wanted to see certain things happen in Ukraine in order to benefit Trump, so he went around U.S. officials and career diplomats, a person familiar with the matter told The Washington Post.

Hill met with lawmakers from the three House committees investigating Trump's July 25 phone call with Ukrainian President Volodymyr Zelensky. Throughout her 10-hour, closed-door testimony, she shared her concerns over Giuliani's role in Ukrainian foreign policy, the Post says. Hill was a member of the National Security Council, but left one week before Trump's call with Zelensky.

Hill also reportedly praised Marie Yovanovitch, the former ambassador to Ukraine, and told lawmakers she was angry when Yovanovitch was removed in May, after Giuliani pressured Trump to recall her from the post. Last week, Yovanovitch testified as part of the impeachment inquiry, and said Giuliani and some of his Ukrainian allies saw her as a threat, standing in the way of their political and financial interests. Catherine Garcia

Secretary of State Mike Pompeo's former senior adviser Michael McKinley is set to testify privately on Wednesday before the three Congressional committees leading the House impeachment inquiry, two officials involved in the matter told The Washington Post on Monday.

McKinley, a career diplomat who served as ambassador to Afghanistan, Brazil, Colombia, and Peru, stepped down last week. He was not directly involved with Ukraine, and reportedly resigned because he felt Pompeo did not do enough to publicly support State Department personnel caught up in the Ukraine scandal.

A person with knowledge of the matter told CNN McKinley will appear for a transcribed interview, indicating he is not coming under subpoena. Catherine Garcia