BAGHDAD, Sept 13 (Reuters) - The U.S. military said on Thursday an Iranian-made rocket was believed to have been used in an attack that killed one person on the headquarters of the American military in Iraq this week.
Military spokesman Major-General Kevin Bergner said it appeared followers of the anti-American Shi'ite cleric Moqtada al-Sadr were responsible for the attack on Tuesday.
"The attack used a 240 mm rocket, which is a weapon that these groups have received from Iranian sources in the past and recently used in other attacks against coalition forces," Bergner said at a news conference.
The incident comes at a time of heightened tensions between Washington and Tehran, with U.S. officials stepping up accusations that Iran is supplying weapons to Iraqi Shi'ite militias to kill U.S. soldiers, a charge Iran denies.
U.S. commanders say that apart from rockets and mortars, sophisticated roadside bombs made from Iranian components have killed scores of U.S. troops.
While Bergner would not confirm the rocket hit the large Camp Victory military base near Baghdad airport, he said the attack killed one person and wounded 11 others.
In a statement late on Tuesday, the military said one third country national was killed and 11 multinational troops wounded in an "indirect fire" attack on the base, which is less prone to attack than other U.S. facilities given its size and location.
Initial assessments of the rocket showed that it was Iranian-made, Bergner said.
"We know that some of the elements of the Jaish al-Mahdi rely on Iranian sources of funding, training and weapons like this," Bergner said, using the Arabic name for the Mehdi Army.
He said the attack was launched from a district in western Baghdad controlled by Sadr's Mehdi Army militia.
Bergner warned followers of Sadr to heed a recent order from the cleric to halt armed activity.
"On Tuesday, it appears some of these criminal elements ignored Sadr's pledge and launched a rocket attack against a coalition base," Bergner said.
"We will show restraint in dealing with his followers who uphold his commitment. However, Iraqi and coalition forces will not show the same restraint against criminals who continue to target civilians and security forces."
Sadr in late August ordered the suspension of all Mehdi Army operations for up to six months, in what was seen as a move to re-establish his control over the militia, which the U.S. military says has fragmented into splinter groups.
But Sadr aides have said the order might not last if U.S. and Iraqi forces do not stop detaining the cleric's supporters.
Bergner said there were indications some Mehdi Army members were respecting Sadr's pledge.