WASHINGTON (Reuters) – Explosions that rocked the capital of Afghanistan on Tuesday were not U.S. strikes in response to the terror attack on America, but may be the Afghan opposition seeking revenge for the assassination of its leader, U.S. officials said.

“That is not a U.S. strike,” a senior Pentagon official said.

Another U.S. official said the apparent rocket attack was not a method the United States would use.

“This has nothing to do with the United States, and it might be the work of the Northern Alliance responding to the attack which killed (Ahmad Shah) Masood,” the official said on condition of anonymity.

U.S. officials believe Masood, the Afghan opposition chief who led the fight against the ruling Taliban, died in a suicide bombing on Sunday, although his aides said he had survived.

The United States believes Saudi-exile Osama bin Laden, who lives in Afghanistan, may be linked to the terror attack on America on Tuesday.