R epublican leaders of the U.S. Congress said on Tuesday that they were focused on improving background checks for potential gun buyers, less than two weeks after 17 people were killed at a Florida high school by a man with an AR-15 assault weapon. The second-deadliest shooting at a U.S. public school has reignited the long-running national debate over gun rights, prompting President Donald Trump to suggest arming teachers, raising the minimum age to buy firearms and banning devices known as bump stocks. Some have suggested bringing back a ban on assault weapons, but House of Representatives Speaker Paul Ryan told a news conference, ""We shouldn't be banning guns from law-abiding citizens. We should be focusing on making sure that citizens who should not get guns in the first place don't get those guns." Echoing Ryan, the No. 2 Senate Republican, John Cornyn, urged lawmakers to pass a bill to tighten the federal background check system. Prosecutors have said that Nikolas Cruz, 19, carried out the Feb. 14 rampage at Marjory Stoneman Douglas High School in Parkland, Florida, an affluent Fort Lauderdale suburb, with a legally purchased rifle. Federal and local law enforcement agencies have acknowledged receiving multiple warnings about Cruz's potential for violence. Trump has been under pressure to show he is responding without alienating Republicans who oppose restrictions on gun rights. In a Monday meeting with more than 35 governors he suggested arming teachers and reopening mental hospitals as ways of preventing school attacks. The National Rifle Association has opposed moves to restrict gun sales and helped block efforts for national legislation following the 2012 massacre of 26 young children and educators in Newtown, Connecticut, the deadliest shooting at a public school in U.S. history. Senate Democratic leader Charles Schumer said Congress must try again to pass meaningful gun legislation, starting with a measure guaranteeing comprehensive background checks for gun purchases. "It's outrageous that so many guns are sold with no background check whatsoever," Schumer said on the Senate floor. "We cannot settle for half-measures. Not after what happened in Florida. Not after so many tragedies." Florida lawmakers and the state's Republican governor, Rick Scott, have proposed raising the minimum age to buy assault weapons to 21, from 18. In a party-line vote, the Republican-led state House Appropriations Committee on Tuesday voted to create a program under which trained teachers would carry guns in schools, the Tampa Bay Times reported. The measure, which also would raise the age to buy a gun to 21 and impose three-day waiting periods to buy guns, would need approval from the full state legislature and governor to take effect. CRUZ TO PROVIDE DNA The Florida court where Cruz faces 17 counts of premeditated murder on Tuesday canceled a hearing where prosecutors had been scheduled to seek hair and DNA samples from the suspect. Broward County prosecutors and Cruz's publicly appointed defender, Gordon Weekes, reached a deal late Monday to provide those samples, making the hearing unnecessary, Weekes said. "There was no reason to push back," Weekes said. "It was a routine motion." Circuit Judge Elizabeth Scherer, who is hearing the case, on Monday rejected a request by defense attorneys to recuse herself from the case. They had argued that she had shown herself to favor the prosecutors. Cruz's case is due to return to court on Wednesday for a hearing to determine whether he has sufficient assets to pay for his own defense, Weekes said. Cruz's mother died in November. Local law enforcement and the Federal Bureau of Investigation have faced criticism that they failed to properly look into multiple tips that Cruz had the potential and capacity for violence. Broward County Sheriff Scott Israel has been criticized for his department's response to the shooting, including the fact that an armed school resource officer stationed at the school stayed outside during the attack. The officer through an attorney on Monday said he remained outside because that was where he believe the gunfire was occurring.