Updated: 5:59 p.m.

President Obama and New York Mayor Michael Bloomberg (I) on Wednesday gave their blessing to the compromise gun control legislation crafted by Sens. Joe Manchin (D-W.Va.) and Pat Toomey (R-Pa.).

In a statement, Obama stressed that he wanted gun legislation that does more than the Manchin-Toomey bill, but said progress is progress.

"This is not my bill, and there are aspects of the agreement that I might prefer to be stronger," Obama said. "But the agreement does represent welcome and significant bipartisan progress. It recognizes that there are good people on both sides of this issue, and we don’t have to agree on everything to know that we’ve got to do something to stem the tide of gun violence."

Bloomberg, who has been even more outspoken than Obama on the need for new gun laws, said he would push hard for the bill, which would require background checks on all commercial gun transactions.

"This bill will not only help keep guns out of the wrong hands; it will help save lives and keep our communities safe," Bloomberg said in a statement released by Mayors Against Illegal Guns, a group he founded. "Our bipartisan coalition of more than 900 mayors strongly supports this bill and looks forward to working with other leaders, including Sens. (Charles) Schumer and (Mark) Kirk who have worked tirelessly on this issue, to do all we can to ensure its passage.”

Bloomberg has spent millions of his personal fortune pushing for stricter gun-control measures and personally thanked the senators involved. His group also announced it would cease running ads in Pennsylvania targeting Toomey -- a sign to the dozen or so other senators being targeted by Bloomberg's ads.

"I want to thank Sens. Manchin and Toomey for their determination to find common ground on a bill that Democrats and Republicans can fully support," Bloomberg said.

Another pro-gun control group, the Brady Campaign to Prevent Gun Violence, meanwhile gave a less enthusiastic nod of approval to the bill.

“While we continue to review the draft bill, we believe a majority of the components are a good step forward to reducing gun violence," the group said in a statement.

The White House and Democrats in Congress have been pushing for universal background checks on nearly every kind of sale, in addition to an assault weapons ban and a ban on high-capacity magazines -- though those proposals don't appear to be going anywhere.

Bloomberg's sign off lends additional credibility to the compromise bill among gun-control supporters, but it remains to be seen whether conservative Republicans will join forces with Toomey and Kirk (R-Ill.).

Heritage Action, the political arm of the conservative Heritage Foundation, which is headed by former senator Jim DeMint (R-S.C.), on Wednesday morning came out against the compromise bill, as did the National Rifle Association.

"Expanding background checks at gun shows will not prevent the next shooting, will not solve violent crime and will not keep our kids safe in schools," the NRA said in a statement. "While the overwhelming rejection of President Obama and Mayor Bloomberg's 'universal' background check agenda is a positive development, we have a broken mental health system that is not going to be fixed with more background checks at gun shows."

Another Republican balking at the Manchin-Toomey proposal is Sen. Tom Coburn (R-Okla.), who had been working with Democrats on a separate piece of compromise legislation.

"The Manchin-Toomey proposal is a good faith but unworkable plan," Coburn said. "The proposal will impose new taxes and unreasonable burdens on law-abiding citizens. The agreement also prioritizes collecting records over protecting citizens."