Although President Trump decided not to launch a military strike against Iran, the two sides continue to spar verbally.

Iran said it would respond firmly to any U.S. threat against it, Iran's Tasnim news agency reported on Saturday, one day after Trump said he called off a military strike to retaliate for Iran shooting down a U.S. drone on Thursday. Trump, though, told NBC News if the time for war does come there will be "obliteration like you've never seen before."

Iran responded in kind. "We will not allow any of Iran's borders to be violated," Iranian foreign ministry spokesman Abbas Mousavi told Tasnim. "Iran will firmly confront any aggression or threat by America." Abolfazl Shekarchi, the senior spokesman for Iran's armed forces, told Tasnim that "any mistake by Iran's enemies," especially the U.S., would "be like firing a powder keg that will burn America, its interests, and its allies to the ground." Tim O'Donnell

President Trump sent Senate Minority Leader Chuck Schumer (D-N.Y.) a letter on Thursday so harsh that Schumer's office said he apologized for it before the missive was even delivered.

Earlier in the day, Schumer wrote his own letter to Trump regarding shortages of ventilators and personal protection equipment at hospitals treating coronavirus patients. Schumer asked Trump to choose someone with a military background to oversee production of medical equipment under the Defense Production Act, adding, "America cannot rely on a patchwork of uncoordinated voluntary efforts to combat the awful magnitude of this pandemic. The existing federal leadership void has left America with an ugly spectacle in which states and cities are literally fending for themselves, often in conflict and competition with each other."

Schumer's office told Politico the senator and Trump spoke twice on Thursday afternoon, and at one point, Trump said he was in the process of sending a "very nasty letter" to Schumer. Trump promised to try to stop it from going out, and said he would apologize if he wasn't successful.

The letter wasn't intercepted, and made it to Schumer. Trump wrote that Schumer was to blame for the high number of coronavirus patients in his state, with New York City "unprepared" because of "the impeachment hoax." He told Schumer he "never knew how bad a senator you are for the state of New York," and pushed back at criticism that the government has responded too slowly to the pandemic, despite having months to prepare. "As you are aware, the federal government is merely a backup for state governments," he said. "Unfortunately, your state needed far more of a backup than others."

In response, Schumer told MSNBC's Chris Hayes that he was "appalled" by the letter, and said it was time for Trump to "stop the pettiness — people are dying." As of Thursday night, 5,850 people have died in the United States from coronavirus. Catherine Garcia

Treasury Secretary Steven Mnuchin on Thursday said a $349 billion coronavirus rescue loan program for small businesses will be "up and running" on Friday, even as lenders express confusion over how they will issue the loans.

The program aims to keep small businesses like salons and restaurants afloat during the coronavirus pandemic. Business owners can get loans of up to $10 million to make payroll for eight weeks or cover rent, utilities, and other expenses. Mnuchin admitted not all lenders will be able to issue loans on Friday, but still encouraged business owners to apply. "You get the money, you'll get it the same day, you use it to pay your workers," he said. "Please bring your workers back to work if you've let them go."

Tony Wilkinson, president of the National Association of Government Guaranteed Lenders, told Reuters "we anticipate more demand than supply. We've got to get our lenders comfortable with the rules so that we know that when we originate a loan, counting on a government guarantee, that we're doing the things necessary so we can actually have the government guarantee."

Applications will be accepted on Friday, Wilkinson said, but it's anyone's guess how many will be approved. "They will process and close them after they know what the rules are," he said. JP Morgan Chase informed clients on Thursday night that they were "still awaiting guidance" from the Small Business Administration and Treasury, and "as a result, Chase will most likely not be able to start accepting applications on Friday, April 3rd, as we had hoped." Catherine Garcia

After being turned away from ports in South America, Holland America's Zaandam cruise ship was allowed to dock at Port Everglades in Fort Lauderdale, Florida, on Thursday afternoon.

Nine people on board the ship have tested positive for the COVID-19 coronavirus. Holland America's owner, Carnival Corp., said there are 45 passengers who are mildly sick, and they will stay on the ship to recover. The company reported that 10 people on board are in need of urgent medical attention, and four elderly passengers have died, with at least two due to COVID-19.

The Zaandam set sail from Buenos Aires on March 7, and was supposed to have stops in Chile and other South American ports before heading to Fort Lauderdale. As the coronavirus continued to spread, the Zaandam was not allowed to dock at its scheduled ports. The last time passengers and crew members were able to get off the boat was on March 14, and passengers have been self-quarantining in their rooms since March 22.

With nowhere else to go, the Zaandam waited off the coast of Panama, and its sister ship, the Rotterdam, came to its aid, picking up healthy passengers and taking them on board. Holland America, Carnival Corp., and Florida officials spent days working on an agreement that allowed the Zaandam and Rotterdam to disembark passengers at Port Everglades. Because of the number of COVID-19 cases in Florida, local officials were concerned about overwhelming hospitals with the sick ship passengers.

There are 1,250 passengers and 1,186 crew members on the Zaandam and Rotterdam, The Associated Press reports. Florida Gov. Ron DeSantis (R) said passengers and crew who do not show symptoms of the virus will be put on private buses, driven to local airports, and directly boarded onto airplanes. Holland America said most will be going home on charter flights. Catherine Garcia

Confirmed cases of the new coronavirus surpassed one million on Thursday, with nearly a quarter of the cases reported within the United States, the Johns Hopkins Coronavirus Resource Center reports. The global death toll now exceeds 51,000, while nearly 209,000 people have recovered from COVID-19.

The million-case mark is an alarming new milestone in the global pandemic. Some 171 countries have reported the disease within their borders, and a third of the world — some 2.6 billion people, more than were alive to witness World War II — is now living under lockdown.

"In a totally rational world, you might assume that an international pandemic would lead to greater internationalism," historian Mike Davis recently told The Guardian. "In a rational world, we would be ramping up production of basic essential supplies — test kits, masks, respirators — not only for our own use, but for poorer countries, too. Because it's all one battle. But it's not necessarily a rational world. So there could be a lot of demonization and calls for isolation. Which will mean more deaths and more suffering worldwide." Jeva Lange

New York City Mayor Bill de Blasio issued a recommendation Thursday to wear face coverings when going outside, and the Centers for Disease Control and Prevention is reportedly set to do the same.

The public should use homemade cloth face coverings when outside and reserve medical-grade masks for health care workers, a draft CDC document obtained by Stat News reveals. A CDC official later told The New York Times the same guidance would soon be issued.

Los Angeles Mayor Eric Garcetti already told his city to wear masks on Wednesday. Like the CDC guidelines are set to recommend, de Blasio told New Yorkers not to buy N95 masks that hospital workers desperately need.

The White House's top coronavirus doctor Anthony Fauci said Tuesday that the CDC would consider issuing a mask recommendation once they were more widely available and that the coronavirus task force would be discussing the proposal that day. Kathryn Krawczyk

The United States Navy has removed the captain of an aircraft carrier who sounded the alarm over a COVID-19 outbreak aboard his ship, NBC News and Axios report. Capt. Brett Crozier, who commands the USS Theodore Roosevelt, had sent a stern four-page letter to his superiors on Monday begging for help containing the outbreak, in which some 150 to 200 sailors had reportedly tested positive out of his nearly 5,000-person crew.

Crozier's letter leaked to the San Francisco Chronicle, and expressed fears that the Theodore Roosevelt was unable to follow quarantine social distancing guidelines when it was forced to dock in Guam. "This will require a political solution but it is the right thing to do," Crozier had written. "We are not at war. Sailors do not need to die. If we do not act now, we are failing to properly take care of our most trusted asset — our Sailors."

Acting Secretary of the Navy Thomas Modly reportedly relieved Crozier of duty over "a loss of trust and confidence." The Washington Post adds that the Navy specifically removed him due to "becoming increasingly convinced that he was involved in leaking the letter to the media to force the service to address his concerns."

Crozier will reportedly keep his rank and remain in the Navy after being relieved of his duty. Jeva Lange