Sen. John McCain (R-Ariz.) on Monday urged the United States to advocate an "overthrow" of embattled Iranian President Mahmoud Ahmadinejad's regime.

The senator's suggestion — which he stressed could be done without military force — differs greatly from the tone taken by both White House officials and numerous other lawmakers, who have recently exhorted Iran to offer "immediate and unfettered access" to international inspectors.

"[T]he solution, I think, not only lies with an attempt to impose sanctions on Iran ... I have very serious doubts as to whether Russia and China will be able to cooperate with sanctions that have significant effect on Iran," McCain told Fox News.

"But I think you left out something, and that is our advocacy for regime change in Iran," the senator added. "And I don't mean through military action, [but] by helping, supporting, assisting in a variety of ways, including Internet access and other encouragement of elements within Iran, to overthrow the regime."

McCain might be the first lawmaker this week to suggest Ahmadinejad's ouster, but he is hardly the only member of Congress clamoring to punish Iran for its clandestine nuclear program.

Soon after evidence surfaced on Saturday that Iran constructed a secret uranium refinement facility in the city of Qom, lawmakers began demanding a new round of sanctions on Tehran. Their calls grew more strident just two days later, after Ahmadinejad authorized a series of medium- and long-range missile tests — a move the White House quickly condemned as "provocative."

Despite this latest diplomatic row, the Obama administration still plans to engage Iran during a meeting of the P5+1 — a coalition of British, Chinese, French, German, Russian and U.S. negotiators — scheduled for Oct. 1. McCain, however, expressed doubt on Monday that the meeting would do any good.

"The talking that's going to take place on the first of October, I'm not optimistic, obviously," McCain said. "But I also think we have to sit down and talk turkey to the Russians and the Chinese and try to make them understand that if there is conflict in the Middle East, it's not in Russia or China's national security interest either in the long run."