The White House said Wednesday it would be "unproductive and unhelpful" for Democratic leaders of Congress to visit Iran.
The criticism came a day after House Foreign Affairs Committee Chairman Tom Lantos told reporters has been trying for 10 years to obtain a visa to visit with leaders in Teheran.
In response, Lantos, a Democrat, said Wednesday: "Members of Congress are not simply potted plants, though the White House would like them to be."
"I am ready to go," Lantos had said on Tuesday. "And knowing the speaker, I think she might be."
However, a spokesman for the leader of the House of Representatives, Speaker Nancy Pelosi, said she had had no intention of going to Iran.