Republican presidential nominee Mitt Romney said he delayed the start of an Ohio campaign stop on Friday to watch on TV the memorial ceremony for four Americans killed during the attack on the U.S. Embassy in Libya.

Flag-draped caskets carrying the bodies of Ambassador Chris Stevens, diplomat Sean Smith and guards Glen Doherty and Tyrone Woods were flown in to Joint Base Andrews in Maryland on Friday.

Romney led the crowd at his Ohio event in a moment of silence to honor those killed.

His running mate, Congressman Paul Ryan, was stumping in the crucial battleground state of Virginia.

During an earlier stop in Washington, D.C., Ryan linked the current Middle Eastern violence to what he called the failures of President Barack Obama's administration.

"Mobs storming American embassies and consulates. Iran, four years closer to gaining a nuclear weapon. Israel, our best ally in the region, treated with indifference bordering on contempt by the Obama administration," said Ryan. "Amid all of these threats and dangers, the one thing we do not see is steady, consistent American Leadership."

Before attending the service honoring the four killed in Libya, Obama joined first lady Michelle Obama in greeting the U.S. Olympic team at the White House.

His campaign said Friday it will add a stop in Ryan's home-state of Wisconsin to their agenda.