U.S. military chief says clock ticking on Iran nuke

WASHINGTON (Reuters) - The top U.S. military officer warned on Tuesday that time is running out for dialogue with Tehran to avoid either a nuclear-armed Iran or a possible military strike against the Islamic Republic.

Admiral Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, said it is critical for diplomatic efforts to reach a solution before Iran develops a nuclear weapon or faces an Israeli or U.S. strike to turn back its nuclear program.

"That window is a very narrow window," Mullen told an audience at the Center for Strategic and International Studies, a Washington think tank.

"There's a great deal that certainly depends on the dialogue and the engagement," he said. "I'm hopeful that that dialogue is productive. I worry about it a great deal if it's not."

Mullen noted that some forecasters believe Iran could be as little as a year away from developing a nuclear bomb, adding: "The clock has continued to tick."

The Obama administration hopes to coax Tehran into negotiating over its nuclear program. Washington and its allies say the program is aimed at producing nuclear weapons, but Iran insists it is a civilian electricity program.

Israel has said a nuclear-armed Iran would be a threat to its existence and points to Iranian President Mahmoud Ahmadinejad's calls for Israel to be wiped off the map.

That has raised concerns that Israel could ultimately carry out a military strike against Iranian nuclear sites.

U.S. President Barack Obama said in an interview the United States had "absolutely not" given Israel a green light to attack Iran over its nuclear program, but he said Washington cannot "dictate to other countries what their security interests are."

"It is the policy of the United States to try to resolve the issue of Iran's nuclear capabilities in a peaceful way through diplomatic channels," Obama told CNN during his trip to Russia.

Vice President Joe Biden said in an interview with ABC's "This Week" program on Sunday that Israel had a sovereign right to act in its best interest in dealing with Iran's nuclear ambitions. The comment was seen by some as giving Israel a green light to attack.

Mullen told his audience that Washington must keep all options on the table as it pursues dialogue with Iran, "including certainly military options."

But he said a military strike -- like the development of an Iranian nuclear bomb itself -- would be "very destabilizing" for the Middle East and pose unpredictable consequences for U.S. allies and interests.

"It (a military strike) is a really important place to not go, if we can not go there in any way, shape or form," the admiral said.