KABUL (AFP) - Three foreign soldiers were killed in Afghanistan on Thursday, bringing to 507 the number of international troops killed in the country since the beginning of the year. Two of the soldiers were killed in separate attacks in southern Afghanistan, according to statements issued by NATOs International Security Assistance Force (ISAF). The third soldier was killed by an improvised explosive device, or IED, the weapon of choice of the Taliban insurgency, whose main bastion is in southern Afghanistan. The soldiers nationalities were not disclosed, in line with NATO policy. The latest overall death toll for foreign troops in Afghanistan this year is rapidly closing in the number registered in all of 2009, which at 521 is deadliest year since the start of the war in late 2001. The figure of 507 deaths for foreign troops killed in Afghanistan this year includes 331 US soldiers and is based by AFP on figures compiled by the independent icasualties.org website. US General David Petraeus, the commander of US and NATO forces in Afghanistan, has that the deployment of foreign forces in Afghanistan would reach its full strength of 150,000 this month. Meanwhile, Taliban-linked rebels killed five Afghan security guards in an attack on Thursday. Five security guards were killed in Ghazni, an official said. Militants attacked a security post at a road construction site, killing the privately employed guards, provincial spokesman Ismail Jahangir told AFP. Two other guards were wounded and another two missing, he said. Taliban spokesman Zabi-hullah Mujahid claimed responsibility in a telephone call to AFP, saying the missing guards had been involved in planning the attack and were with the militants. There was no claim of responsibility for the ISAF death. A NATO air strike killed eight militants in the northern province of Kunduz overnight, the military said. Abdul Wahid Omarkhail, the chief of Chahar Dara district, where the strike happened, put the death toll at 12. In the volatile Arghandab district of southern Kandahar province, police said six Taliban were killed and another 16 wounded in a raid on their hideout.