US president Barack Obama signed a strategic partnership agreement with his Afghan counterpart Hamid Karzai early this morning which paves the way for US forces to stay beyond 2014.
It means the US will withdraw 23,000 of its 90,000 troops deployed in the country by the end of summer.
But it obliges Afghanistan to provide US personnel access to and use of Afghan facilities in 2014 and beyond.
Foreign forces were scheduled to leave Afghanistan by the end of that year.
Hours after the deal was signed militants launched an attack on a foreign military base in eastern Kabul, killing eight and injuring 17.
A police source said that the dead included a foreign security guard, five civilians and two suicide bombers.
Taliban spokesman Zabiullah Mujahid claimed responsibility saying it was a "reaction to Obama's visit to Afghanistan."
Foreign Minister Alistair Burt's admission that the Cameron government has "supported" a survey of attitudes to US drone strikes in Pakistan's tribal areas amounts to a tacit admission of British involvement.