10 things you need to know today: January 18, 2016

Democratic frontrunner Hillary Clinton and Sen. Bernie Sanders (D-Vt.) clashed Sunday over key issues like gun control and Wall Street in the last presidential debate before the Feb. 1 Iowa caucuses. Sanders accused Clinton of being too close to Wall Street, a major source of her campaign contributions. Clinton tried to puncture the grassroots appeal that has helped Sanders surge in the polls, saying he had voted "with the NRA" several times against gun control. The third candidate, low-polling former Maryland governor Martin O'Malley, said both his rivals had been "inconsistent" on gun control while he signed sweeping gun laws.

Americans are holding marches and other events on Monday to mark the 30th anniversary of the federal holiday honoring civil rights leader Martin Luther King Jr., who was assassinated in 1968. Civil rights activists in South Carolina are holding a march to the state capitol in Columbia, where King Day at the Dome has been held annually since 2000. In past years, participants have called for removing the Confederate battle flag removed from Statehouse grounds, which state officials ultimately did in July. The state NAACP has made "education equity" the theme of this year's rally.

Iraqi security forces conducted house-to-house searches in a Baghdad neighborhood Monday morning after three Americans were reportedly kidnapped by militiamen in the area over the weekend. The Americans, all of Iraqi origin, were taken from their interpreter's apartment in southern Baghdad's Dora neighborhood, and taken to Sadr City, an Iraqi government intelligence official said. The U.S. embassy confirmed that "several" Americans had gone missing.

President Obama on Sunday praised the diplomatic efforts of Secretary John Kerry and others in Iran following the U.N.'s recognition of Iran's compliance with the nuclear deal, and Iran's release of five U.S. prisoners. "The U.S. has never been afraid to pursue diplomacy with our adversaries," Obama said, before adding that the U.S. still has many areas of disagreement with Iran. Iranian President Hassan Rouhani also celebrated the nuclear agreement Sunday and the corresponding lifting of economic sanctions, saying the deal "opens a new gate" to prosperity for the nation.

The price of Brent crude oil, an international benchmark, briefly fell to a 12-year low below $28 a barrel on Monday after the lifting of sanctions against Iran. The United Nations declared that Iran had complied with the July international deal to curb its nuclear program, clearing the way over the weekend for the removal of sanctions that had cut Iran's oil sales. Iran is beginning efforts to boost its production by 500,000 barrels a day, adding to a global glut.

A Utah police officer, Douglas Barney, was fatally shot in the head on Sunday while chasing a "violent fugitive," police said. He was the first U.S. police officer killed in the line of duty in 2016. Barney was searching for 31-year-old Cory Lee Henderson and a female companion, who allegedly fled after their BMW was involved in a traffic accident that left the occupants of the other vehicle seriously injured. Officers later killed Henderson in an exchange of gunfire that left another officer, Jon Richey, with three gunshot wounds.

French President Francois Hollande on Monday declared that his country was in "a state of economic and social emergency." Hollande, who hopes to win reelection next year, announced a $2.2 billion plan to revive hiring and gain lost ground in a rapidly changing world economy. The plan calls for creating 500,000 vocational training programs, boosting subsidies for small companies that hire young workers, and helping businesses hire more apprentices. "Our country has been facing structural unemployment for too long and it needs to reform," he said.

International tennis authorities on Monday denied suppressing evidence of match fixing. The statement came in response to a joint report by BuzzFeed and the BBC alleging that the Tennis Integrity Unit, which monitors professional tours like Wimbledon, had failed to act on suspicions of match fixing, fueled by suspicious betting patterns. The BBC reported that 16 players who have ranked in the top 50 were repeatedly flagged on suspicion of throwing matches, but were allowed to continue playing.

British lawmakers are scheduled on Monday to debate a call for banning U.S. Republican presidential frontrunner Donald Trump from the U.K. because of his proposal to temporarily bar Muslims from entering the U.S. More than 500,000 people have signed an online petition calling for his ban from the U.K., and under British law, any verified petition backed by 100,000 people must be considered for debate in Parliament. The debate, however, won't result in a binding vote.

SpaceX failed Sunday in its third attempt to land a Falcon 9 rocket on a barge in the open ocean. The rocket was launched from Vandenberg Air Force Base in California and performed well in flight. It approached the floating landing pad off San Diego at a proper touchdown speed, but one of its legs collapsed, causing the Falcon 9 booster to tip over and explode. "Well, at least the pieces were bigger this time," SpaceX CEO Elon Musk tweeted. SpaceX is developing reusable boosters to reduce the cost of its space missions.