UPDATE 2-Two U.S. soldiers killed in complex Afghan attack

(For full coverage on Afghanistan, double click on [ID:nAFPAK])

* Two U.S. soldiers killed in complex attack

* Air strikes kill up to 30 insurgents

* Taliban accused of firing white phosphorus round

By Paul Tait

KABUL, July 4 (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 stabilise Afghanistan [ID:nSP401743].