DOSWELL, Va. — Mitt Romney plans to campaign in Pennsylvania this weekend, the clearest indicator yet that the Republican nominee believes he can snatch the state and its 20 electoral votes from President Obama.

Two campaign officials confirmed that Romney would stop in the Philadelphia area on Sunday amid a cross-country tour of battleground states. His running mate, Rep. Paul Ryan (Wis.), has scheduled a campaign stop in Harrisburg, Pa., on Saturday.

This move comes as Republicans are making a play for Pennsylvania, which both sides had considered out of reach for Romney until recently. Romney and his allies are running television ads in the state, and an official at the Republican National Committee said Thursday that the party committee has bought $2.5 million worth of broadcast television advertising there, as well as roughly $500,000 in radio ads.

The news of Romney's trip was first reported by The Daily.

“Our campaign's decision to travel to and campaign in Pennsylvania is just the latest example of how the race is breaking toward Governor Romney and allowing our campaign to be on offense. President Obama is playing defense in states once considered safely in his column,” said a Romney campaign adviser, who requested anonymity because the candidate’s travel plans have not been announced.

On a conference call Wednesday, Romney advisers played up GOP chances in a trio of Democratic-leaning states – Pennsylvania, Minnesota and Michigan.

“In any one of these states, Governor Romney has an excellent shot of winning,” senior strategist Russ Schriefer said. “Can we win all of them? Probably not. But can we win some of them? I think so.”

Although polls show Romney narrowing the gap with Obama in Pennsylvania, winning the state will be a challenge for the Republican. A Franklin and Marshall College poll of likely Pennsylvania voters released Wednesday had Obama leading Romney 49 percent to 45 percent, although the president enjoyed a 9-percentage point lead there a month ago.

The Obama campaign said Romney's play in Pennsylvania is a sign that his campaign is "flailing."

"In an act of sheer desperation, Mitt Romney and Paul Ryan are going all in in Pennsylvania, following the lead of every Republican presidential candidate since 1992 who have made last ditch investments in the Keystone State," Obama campaign spokesman Michael Czin said. "Not one of them carried the state. With less than a week to go and consistently down in must-win states, Mitt Romney's campaign is desperately trying to find a path to 270 electoral votes with no avail."

Sen. John McCain visited Pennsylvania on the Sunday before the 2008 election. He lost the state by 10.3 points; the Real Clear Politics average on the eve of the election had him down by 7.3.