Two U.S. soldiers killed in complex Afghan attack

KABUL (Reuters) - Two U.S. soldiers were killed when their base in southeast Afghanistan came under attack on Saturday, the U.S. military said, two days after a major operation against the Taliban was launched in the south.

The attack included an attempted suicide truck bombing of the base in the Zirok district of southeastern Paktika province, local officials said. As many as 30 Taliban insurgents might have been killed when troops called in air strikes, they said.

It came after thousands of U.S. Marines launched a major offensive in southern Helmand province, a Taliban stronghold and major opium poppy producing area, on Thursday, the first big operation of U.S. President Barack Obama's new regional strategy to defeat the Taliban and stabilize Afghanistan.

The Marines and other forces have so far met little resistance and there have been no reports of big reprisal attacks by the Taliban or its allies since Operation Khanjar, or Strike of the Sword, began in Helmand.

Another seven U.S. soldiers and two Afghan troops were wounded in Saturday's attack on the combat outpost near Zirok, Lieutenant Commander Christine Sidenstricker said.

"It was a complex attack that started with small-arms and indirect fire on the post, then an improvised explosive device went off," Sidenstricker said.

"Air strikes were called in some time after," she said.

The international coalition in Afghanistan said in a later media statement that multiple rocket and mortar rounds had been fired at the outpost, one of which contained white phosphorus.

Afghanistan's Taliban have denied using the chemical, which bursts into flame on contact with the air and can cause horrific burns. A coalition spokesman said about 70 incidents of insurgents using or possessing white phosphorus had been documented since April.

Most commonly used on battlefields as a smokescreen or for illumination, its use to deliberately target people is illegal.

An 8-year-old girl was badly burned by white phosphorus in west Afghanistan in May, with the U.S. military and the Taliban accusing each other of firing the round containing the chemical.

SUICIDE TRUCK BOMB

Hamidullah Zwak, a spokesman for the provincial governor, said a suicide bomber drove a truck toward the base during the Zirok attack but was shot before he could reach it. Explosives in the truck detonated during the shooting, he said.

Taliban spokesman Zabiullah Mujahid said "several Afghan and foreign soldiers were killed." There was no independent verification of his claim.

Zwak said about 30 Taliban fighters were killed in the air strikes but those figures again could not be verified independently. Afghanistan's Interior Ministry said in a statement about 20 insurgents were killed.

The U.S. military said attack helicopters and close air support were called in and at least 10 insurgents were killed.

Saturday's attack came in the same area where a U.S. soldier was reported missing. The soldier has been missing since Tuesday and is believed to have been captured by insurgents.

Some of the most active insurgents in the area include the al Qaeda-linked Haqqani network, against which U.S. and other NATO troops have launched a number of operations in recent weeks.

The network is allied with the Taliban and has been behind several high-profile attacks in Afghanistan.

The U.S. Marines launched their new operation in Helmand with violence in the Taliban-led insurgency at its worst since the austere Islamist group was ousted from government in late 2001.

The new operation was launched after years of stalemate in the south, which provides most of the poppy crop that funds the insurgency, with the hope that it would turn the tide of a war some in Washington say they are not winning.

Its intention is to seize ground from the Taliban and hold it, something overstretched NATO troops have so far been unable to do, and to win the trust of local communities and turn people away from the insurgency.

(Additional reporting by Elyas Wahdat in KHOST and Hamid Shalizi in KABUL; editing by Philippa Fletcher)