The White House reiterated on Wednesday its objection to plans by Democratic leaders of Congress to visit Iran.

"On a day when the U.S. military reports additional evidence of Iran's meddling in Iraq with weapons and training that are being used to kill our soldiers, it's troubling that some Democrats are making travel arrangements to visit Tehran," White House deputy press secretary Dana Perino said at a briefing.

Such trips would be "unproductive and unhelpful - and that applies to all members of Congress, Republicans and Democrats," Perino said.

The spokeswoman made the remarks after Democratic Representative Tom Lantos said he was ready to go to visit Iran. Lantos also suggested that House Speaker Nancy Pelosi would go to Tehran as well.

"Speaking just for myself, I'm ready to go," Lantos told reporters here late Tuesday. "And knowing the speaker, I think she might be."

Both Pelosi and Lantos visited Syria over White House objections last week.

The White House described Pelosi's two-day visit to Syria as "a really bad idea." U.S. President George W. Bush accused Damascus of neither controlling violent elements of militant groups Hamas and Hezbollah as requested by the international community, nor supporting the democratically elected government of Lebanon.

Pelosi's visit to Damascus "does not work" to change Syria's stand on the Middle East issues, Bush said.