THOMAS BEAUMONT/Associated Press

GREENVILLE, S.C. (AP) - Republican presidential candidate Rick Santorum said Saturday the U.S. was wrong to condemn the killing of an Iranian nuclear scientist this week.

The Obama administration's public posture on the death Wednesday of Mostafa Ahmadi Roshan does not reflect the hard line Santorum supports in keeping Iran from obtaining nuclear weapons, the former Pennsylvania senator said while campaigning in conservative upstate South Carolina.

"Our country condemned it. My feeling is we should have kept our mouth shut," Santorum told about 200 people packed into a popular breakfast diner in Greenville.

Santorum is vying to emerge as conservatives' alternative to former Massachusetts Gov. Mitt Romney in the Jan. 21 South Carolina primary. Romney leads in public and private polls of likely voters, although former House Speaker Newt Gingrich is within striking distance, with a week to go before balloting begins.

However, Santorum has risen here since his breakthrough near-tie with Romney in the Iowa caucuses on Jan. 3. He has a robust state organization and is making aggressive inroads with evangelical conservatives, like many of those who were at the Country Ham House Saturday morning.

And while Santorum stresses values issues, he has also argued for a tough stand on Iran's nuclear capability. Responding to a question in Greenville, he said he supports missile strikes to stop its nuclear program, if Iran refuses to submit to inspections.

"If these are people who are developing a weapon to be used to either destroy the state of Israel or to spread terror - a reign of terror - around the world, we shouldn't be sitting on the sidelines and letting it happen," he said. "They cannot have a nuclear weapon, because you, in Greenville, will not be safe."

Santorum was scheduled to campaign later Saturday in the Charleston area.

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