4 Americans killed in Afghan bombing

Four US service members were killed by a bomb blast, with two killed instantly and two later dying of their wounds Thursday, the US said in a statement. No further details were released.
The deaths bring to 25 the number of American service members killed in Afghanistan this month, according to an Associated Press count.
A UN-backed panel has completed most of its investigation into whether the level of fraud in Afghanistan's presidential election will require a runoff, a spokeswoman said yesterday as the US military announced the killing of four more American troops.
Afghanistan's ambassador to the United States says he expects a second round vote will be required.
Rising death tolls and the political crisis brought on by a fraud-marred election have prompted President Barack Obama's administration to review its entire Afghanistan strategy. The White House is considering various options, including a sharp increase in the number of US troops here or shifting the focus to missile strikes and special operations raids against al-Qaeda members hiding in neighbouring Pakistan.