Washington, Dec. 15: In the emotional statement on the Newtown shootings that President Obama delivered from the White House yesterday, it was a single line, spoken as much in anger as in grief, that stood out. The words were cautious and were immediately criticised for being too timid.

But they may have signalled that the long-dormant debate over the nation’s gun laws is about to be re-engaged.

“We’re going to have to come together and take meaningful action to prevent more tragedies like this, regardless of the politics,” Obama said, listing the devastation wrought by other gun violence, from a recent attack in an Oregon shopping mall to the shootings in a movie theater in Aurora, Colorado, in July.

But Mayor Michael R. Bloomberg of New York spoke for many gun-control advocates, who have been frustrated and disappointed by Obama’s failure to embrace the issue, when he said he wanted to hear much more.

“Calling for ‘meaningful action’ is not enough. We need immediate action,” said Bloomberg, who is a leader of a group of mayors against illegal gun ownership.

“We have heard all the rhetoric before,” Bloomberg added. “What we have not seen is leadership — not from the White House and not from Congress. That must end today.”

White House officials professed not to know what Obama’s pledge for “meaningful action” meant. But given Obama’s methodical style, the words were not likely to have been chosen casually. And yet the President stopped short of detailing any new initiatives, like restrictions on high-capacity ammunition magazines or stricter bans on gun buyers with a history of mental illness.