FACTBOX-Security developments in Afghanistan

(Reuters) - Following are security developments in Afghanistan at 3 p.m. British time on Thursday.

HELMAND - About 4,000 U.S. Marines and 650 Afghan troops launched a major offensive in southern Helmand province, a traditional Taliban stronghold, U.S. military commanders said. A U.S. military spokesman said there had been small skirmishes and some minor casualties had been reported. A Taliban spokesman, Qari Mohammad Yousuf, said one Taliban fighter had been killed and two wounded and claimed that 11 foreign troops had been killed or wounded.

PAKTIKA - A U.S. soldier has been missing since Tuesday and was thought to have been captured by insurgents in southeastern Paktika province, the U.S. military said in a statement.

ZABUL - Afghan police killed nine insurgents in Dai Chopan district in southeastern Zabul, the Interior Ministry said in a statement. A tonne of explosives was also uncovered in the operation, it said.

HELMAND - Britain's Ministry of Defence identified as British two soldiers from the NATO-led force who were killed in a bomb attack in southern Afghanistan on Wednesday. They were killed during an operation near Lashkar Gah, it said in a statement.

(Compiled by Golnar Motevalli; Editing by Paul Tait)