U.S. President Barack Obama wants to reinstate an assault weapons ban in the wake of the mass killings in Newtown, Connecticut, his spokesman says.

According to BBC News, Jay Carney said the president was "actively supportive" of a Democratic senator's plan to introduce a bill on the first day of the next Congress.

There could also be moves on ammunition and gun-sale loopholes, Carney said.

The U.S. president has previously stated his support for the reintroduction of an assault weapons ban, which lapsed in 2004. But he has not backed a specific move to do so before now.

"He is actively supportive of, for example, Senator [Dianne] Feinstein's stated intent to revive a piece of legislation that would reinstate the assault weapons ban," Carney said on Tuesday, Dec 18.

The White House press secretary added that Mr Obama was also supportive of other gun legislation, including on high-capacity ammunition clips and against a loophole that allows for gun purchases at gun shows without a background check.

During the presidential campaign, Obama expressed support for the ban on assault weapons during one of three televised debates against Republican candidate Mitt Romney.

"I also share your belief that weapons that were designed for soldiers in war theatres don't belong on our streets," Obama said in the second debate on Oct 16.