"Her going to a state which is without question a sponsor of terror, and having her picture taken with (Bashar) Assad and being seen in a headscarf and so forth is sending the wrong signal to the people of Syria and to the people of the Middle East," the former Massachusetts governor said while campaigning in Johnston, a Des Moines suburb.
"It's a very bad idea to be carrying out a separate and independent foreign policy from the president of the United States," Romney added. "I just don't know what got into her head, to be completely honest with you. I think it was a huge, huge mistake."
Romney's comments came as Pelosi held talks with Assad in Damascus over White House objections. President Bush has denounced the visit, saying it sends mixed messages to Assad's government.
Democrats say the administration's attempts to isolate Syria have failed to force the Assad government to change its policies. The White House accuses Syria of backing terrorism because of its support for the Hezbollah and Hamas militant groups and of destabilizing the Lebanese government. The administration also says Syria is fueling Iraq's violence by allowing Sunni insurgents to operate from its territory.
Earlier, at a news conference at the Iowa statehouse, Romney chastised Democrats in Washington for a standoff with Bush that has held up a bill providing money for the Iraq war. Democrats want to include a timetable for a U.S. troop withdrawal in the bill. Bush has threatened to veto any measure that includes a timetable.
"I'm going to suggest that the Democrats in Washington provide the funding necessary to support the foreign policy which is established by the president of the United States. It is not up to Harry Reid and Nancy Pelosi to dictate to the commanders in the field or to the commander in chief," Romney said of the Democratic leaders of the Senate and House, respectively.
Asked whether he backed Bush's veto threat, the GOP candidate said he would let the president make his own decision on the tactics he employs to ensure troops are funded. Democrats, he said, "can have an up or down vote but putting pork projects into a bill or putting in place various nonbinding resolutions in the bill, these are confusing and unnecessary."