Afghanistan ? A bomb exploded Tuesday near a taxi on a busy Kabul road, killing two Afghans, and a U.S. soldier and seven militants died in fighting in the east – the latest wave of violence threatening Western attempts to rebuild Afghanistan.

The U.S.-led coalition announced it had killed more than 600 Taliban rebels in the past six weeks during an operation with Afghan forces to crush insurgents in the south.

The Afghan government, meanwhile, launched an urgent appeal for more that $75 million to tackle an “imminent food crisis” caused by prolonged drought.

Tuesday’s bomb in Kabul – the latest in a series of recent blasts that have rattled nerves in the capital – killed a man and woman riding in a taxi and wounded four other people, said police official Faiz Ahmad Hotaq.

At least 258 members of the U.S. military have died in Afghanistan, Pakistan and Uzbekistan as a result of the U.S. invasion of Afghanistan in late 2001, according to the Defense Department.