Gates arrived in Afghanistan on the same day that Iranian President Mahmoud Ahmadinejad was supposed to have visited. Iranian state-run media reported Monday that Ahmadinejad’s trip had been postponed until mid-March.

“Iran is playing a double game in Afghanistan,” Gates told reporters on the flight to Afghanistan. “They want to maintain a good relationship with the Afghan government. They also want to do everything they possibly can to hurt us, or for us not to be successful.”

Gates said the Tehran government “will help the Taliban, whether they are providing money” or “some low level of support.”

NYT: Mr. Gates is visiting Kabul during the same week that President Mahmoud Ahmadinejad of Iran is expected in the Afghan capital to meet with Mr. Karzai. Mr. Gates told reporters that Iran was “playing a double game in Afghanistan — they want to maintain a good relationship with the Afghan government, they also want to do everything they possibly to can to hurt us, or for us not to be successful. And they’re trying to thread that.”

Mr. Gates said he believed that Iran was providing money and “some low level of support” to the Taliban in Afghanistan, and that “they also understand that our reaction, should they get too aggressive in this, is not one they would want to think about.”

Geoff Morrell, the Pentagon press secretary, swiftly amended Mr. Gates’s comments on Iran and said that the defense secretary meant to say that any American reaction would occur within Afghanistan, not elsewhere. As Iran has continued its nuclear program despite American and international pressure to curtail it, there has been speculation for years that the United States or Israel might bomb Iran’s nuclear facilities.