Republican presidential front-runner Mitt Romney said Tuesday he was surprised by Rick Santorum's departure from the nomination race and that he has yet to turn to matters such as gathering names of possible running mates.

"I do not even have a list," a buoyant Romney told Delaware voters a few hours after Santorum suspended his campaign and cleared the path for Romney's nomination.

Romney told about 300 people in a steel fabrication plant that Santorum's announcement was unexpected. When a woman asked about his picking a running mate, Romney laughed and said, "I can't tell you when, and I can't tell you who."

Romney said Santorum will continue to play an important role in the Republican Party and the nation's politics. He said he spoke to Santorum earlier in the day and that they discussed ways to move the nation forward.

"This has been a good day for me," he said.

Santorum's announcement in Gettysburg, Pa., didn't include an endorsement of Romney, but the former senator from Pennsylvania said defeating Obama remained a goal.

Romney seemed content to shift slowly into his new role as the largely unencumbered Republican candidate. He made his traditional attacks on President Barack Obama's handling of the economy. His staff said he will attend scheduled events Wednesday in Rhode Island and Connecticut even though those states _ like Delaware _ are safely Democratic in presidential elections and therefore not contested in the fall.

Romney said Democrats are wrong to claim the GOP is waging a "war on women." He held Tuesday's speech at a large women-owned plant in Wilmington and said women have lost large numbers of jobs under Obama's administration.