WASHINGTON - Calls for gun control grow Sunday as Washington mulls what's next after a deadly shooting last week in Connecticut cost the lives of 28 people, most of them children aged 6 and 7.

In Sunday talk shows Washington heavyweights debated on whether the country needs to tighten laws that control assault weapons. California Senator Dianne Feinstein, a top Democrat and leading liberal voice in the Senate, told David Gregory, host of NBC's "Meet the Press" that she is reintroducing a federal ban on assault weapons on the first day of the coming Congress, and urged President Barack Obama to lead on the issue.

"I can tell you that he is going to have a bill to lead on because as a first-day bill I'm going to introduce in the Senate and the same bill will be introduced in the House - a bill to ban assault weapons," Feinstein said. "It will ban the sale, the transfer, the importation and the possession. Not retroactively but prospectively. And it will ban the same for big clips, drums or strips of more than 10 bullets."

New York City Mayor Michael Bloomberg appears in a pre-taped interview on "Meet the Press" in Washington, Dec 15, 2012 in this handout photo supplied by NBC NewsWire Dec 16, 2012. [Photo/Agencies]

New York Mayor Michael Bloomberg, a leading voice for gun control, also said guns should be Obama's top priority. Bloomberg said on "Meet the Press" that if Obama "does nothing during his second term, something like 48,000 Americans will be killed with illegal guns. That is roughly the number of Americans killed in the whole Vietnam War."

The remarks come two days after the massacre at Sandy Hook Elementary School in Newtown, Connecticut -- where a 20-year-old gunman killed 26 people, including 20 children, after killing his mother at her nearby home. The gunman killed himself as first responders closed in.

Assault weapons were banned under the Federal Assault Weapons Ban from 1994 to 2004, but Congress allowed the ban to lapse. Obama has said he would support a reintroducing of the bill.