KABUL (AFP) - Seven soldiers from the Nato-led International Security Assistance Force (ISAF) were killed in a bombing in southern Afghanistan on Thursday, the military said. Seven ISAF service members died following an improvised explosive device attack in southern Afghanistan today, ISAF said in a statement. It did not say which country they were from, where they were killed or give further details of the incident, in line with policy. However, a coalition official speaking to AFP on condition of anonymity said the deaths occurred in Shorabak district, Kandahar province, and came in two successive blasts in the same location. Local border police commander Tafseer Khan Khogyani added that the attack also killed two Afghan policemen and happened as coalition and Afghan forces were on patrol around 20 kilometres from Afghanistans border with Pakistan. As they approached a container, explosives that had been placed inside went off, causing a huge explosion, he said. Responsibility for the blast was claimed by a spokesman for the Taliban. The bombing caused ISAFs highest death toll in a single incident since April 27, when nine Americans - eight troops and a contractor - were killed by an Afghan officer who opened fire at a Kabul military training centre. At least, 199 foreign troops have now been killed in Afghanistan this year, according to an AFP tally based on that kept by the independent website iCasualties.org. Earlier Thursday, a Nato helicopter crashed in a mountainous area of eastern Afghanistan, killing one soldier. The cause of the crash is unknown and is under investigation, ISAF said. It did not release the nationality of the service member who was killed. A Western military official said the helicopter came down in Paktika, which borders Pakistans tribal belt. The incident came two days after a French fighter jet crashed in western Afghanistan, although the crew escaped without injury. There are around 130,000 ISAF service personnel in the war-torn country, around 90,000 of whom are from the United States. Much of Afghanistans worst fighting takes place in the south of the country, particularly in the provinces of Kandahar and Helmand which border Pakistani areas. The Taliban announced the start of their spring fighting season at the end of April. While international forces insist they have been taking the fight to insurgents throughout the winter, coming months will provide a key test of their ability to hold ground in the south taken from the Taliban last year following a troop surge.