KABUL, Dec 17 (Reuters) - A blast was heard in the Afghan capital Kabul on Monday, a Reuters witness said.
The cause of the explosion was not immediately clear. One television station said it took place on a street where several bases for foreign troops are located.
Afghanistan's Taliban movement, and the Haqqani network, one of the most lethal foes of Western troops in Afghanistan, have been blamed for several high-profile attacks in the capital.
The Afghan government is scrambling to improve security ahead of the withdrawal of most U.S.-led NATO combat troops by the end of 2014. (Reporting by Hamid Shalizi; Writing by Michael Georgy; Editing by Jeremy Laurence)