GOP vice-presidential nominee Paul Ryan will make his second trip to Pennsylvania in recent weeks, headlining a rally Saturday at Harrisburg International Airport in Middletown.

The visit comes as the Republican ticket is talking up its chances of expanding the electoral map to historically blue territory including Pennsylvania, Minnesota and Michigan — a move that the Obama campaign has dismissed as political bluster, even as it readies a new round of TV ads in those states.

Ryan last visited Pennsylvania Oct. 20, when he headlined a brief rally at the Pittsburgh airport before heading west to Ohio.

The Middletown stop is part of a four-state swing that will take Ryan on Saturday to the country's three biggest battlegrounds — Ohio, Virginia and Florida — in addition to the Keystone State.

Mitt Romney is planning to campaign in Pennsylvania on Sunday. He has not visited the state in the past 30 days.