Hillary Clinton is bringing back her now-famous "3 a.m." ad, this time using it to highlight for Pennsylvania voters her readiness in an economic crisis.

In the new ad, which John McCain later mocked in a commercial of his own, the campaign recycles footage from the ad that first ran before the March 4 Texas primary questioning whether rival Barack Obama would be fit to handle an international crisis when the presidential phone rings at 3 a.m.

Only this time, the voice-over is a bit different.

"It's 3 a.m., and your children are safe and asleep," the narrator says, again to the backdrop of dark blue-tinged footage of sleeping children. "But there's a phone ringing in the White House and this time the crisis is economic.

"Home foreclosures mounting, markets teetering ... Hillary Clinton has a plan to protect our homes, create jobs. It's 3 a.m., time for a president who's ready."

The ad, released Wednesday, takes a jab at McCain, accusing him of wanting to take no action on the housing crisis. The McCain campaign had a swift retort.

"With ads like that, it's more likely the call at 3 a.m. is 'Senator, you just lost another superdelegate,'" McCain senior adviser Steve Schmidt said.

McCain later launched a Web ad that parodied Clinton's.

The ad starts with the same lines, but then the narrator says: "Hillary Clinton and Barack Obama just said they'd solve the problem by raising your taxes. More money out of your pocket. John McCain has a better plan. Grow jobs, grow our economy ... not grow Washington."

Clinton and her surrogates have sustained the "3 a.m." theme of experience and readiness on the stump ever since the ad first aired. But the ad has become fodder for several candidates. Obama also parodied the commercial last month in Texas.

Click here to see the new Clinton ad.

Click here to see the McCain response ad.  

FOX News' Mosheh Oinounou contributed to this report.