U.S. President Joe Biden asked Americans to stand up to the gun lobby and pressure members of Congress to pass sensible gun laws after the killing of at least 18 children and an adult in a Texas school shooting on Tuesday.

Authorities said an 18-year-old gunman opened fire at an elementary school in south Texas, about 80 miles (130 km) west of San Antonio before he apparently was killed by police officers.

"I hoped when I became president I would not have to do this, again," a visibly shaken Biden said, decrying the death of "beautiful, innocent" second, third and fourth graders in "another massacre."

Their parents "will never see their child again, never have them jump in bed and cuddle with them," he said.

"As a nation, we have to ask, 'When in God's name are we going to stand up to the gun lobby?'"

"We have to act," he said and suggested reinstating the assault weapons ban and other "common sense gun laws."

The shooting hands Biden, already facing the lowest approval ratings of his presidency, another crisis on top of 40-year high inflation rates and the war in Ukraine.

A mass shooting in a Buffalo, New York, grocery store 10 days ago increased pressure from backers of tougher gun laws for the Biden administration to make good its vow to crack down on gun violence.

When he ran for the White House, Biden promised to push gun safety measures and reduce the country's tens of thousands of annual gun deaths. Biden and his fellow Democrats have failed to get enough votes in Congress for background checks for gun purchases or other proposed bills.

The United States is the most heavily armed society in the world, according to the Geneva-based Small Arms Survey, a research group. Small, rural states where gun ownership is widespread have disproportionate influence in the U.S. Senate, where a supermajority of 60 votes is needed to advance most legislation in the 100-seat chamber.

Biden was briefed about the shooting aboard Air Force One as he returned from a trip to Asia, White House press secretary Karine Jean-Pierre said on Twitter. He called Texas Governor Greg Abbott to offer any assistance needed.

"His prayers are with the families impacted by this awful event," Jean-Pierre said.

In a proclamation issued before he landed, Biden ordered the flags at the White House and at U.S. federal and public buildings to be flown at half-staff until sunset on May 28.

Active shooter incidents up 52% last year https://www.reuters.com/world/us/fbi-counts-61-active-shooter-incidents-last-year-up-52-2020-2022-05-24/