UPDATED: Status report on Toomey-Manchin gun talks expected around 5 p.m.

UPDATED: Sen. Pat Toomey kept his head down as he quickly walked past a gaggle of reporters. Sen. Joe Manchin, the West Virginia Democrat who Toomey is working with on a background check compromise, sprinted past several huddled reporters, arms pumping, offering only a hasty, "Gotta go."

But after the party caucuses met for their weekly lunches, Manchin, with one foot inside an elevator, gave one nugget of news: He would provide Democratic leadership an update on his talks with Toomey at 5 p.m.

Majority Leader Harry Reid said he plans to file cloture -- a procedural vote that would end the filibuster Republicans are threatening -- either way on Tuesday night. A vote to limit debate and move to an vote up or down on the package of gun control proposals would be Thursday.

As the closed-door debate continued on Capitol Hill, around 100 gun control advocates gathered outside Toomey's Philadelphia office to encourage his support. Featured was former Gov. Ed Rendell who told the crowd that he'd spoken to Toomey and that the senator would not be supporting a filibuster.

"We want a Toomey-Manchin bill [on background checks] so we can be proud of our senator and proud that a Pennsylvanian played a key part in reaching the solution," Rendell said.

FROM EARLIER: Gun control advocates hope a little positive reinforcement will further encourage Sen. Pat Toomey as talks continue.

Since news broke Friday that the Pennsylvania Republican was working with border state friend Joe Manchin, a West Virginia Democrat, on a bipartisan bill to expand background checks on gun sales, Toomey has been regarded as a would-be savior for new gun laws.

"The Conservative Senator Who May Control Obama's Fate" was the headline of a National Journal article. "Pat Toomey: Gun control's unlikely savior?" asked the Washington Post's political writers. "The Republican Who Can Save Gun Control" wrote liberal news website, Salon.

While the Toomey folks caution not to jump the gun (pun obviously intended), the narrative as the senators return to Capitol Hill after a two-week holiday recess is that Toomey is the Democrats' best chance for victory on at least a key piece of their gun control proposal.

So in keeping with the old adage you catch more flies with honey than vinegar, Mayors Against Illegal Guns, New York City Mayor Mike Bloomberg's group, is airing a new ad commending Toomey for his work on a background check deal.

In the ad, a narrator discusses the need for new laws to stop criminals and the mentally ill from obtaining guns, adding "Senator Toomey understands how important that change is."

But with no deal actually made, and with the understanding that talks can always break down, the ad encourages Pennsylvanians to call Toomey's office to show their support for gun control.