Kabul, Afghanistan ? As thousands of Afghans fled hunger, drought and violence in the north, the country’s interim leader moved Thursday to play down apparent rifts in his new government. The CIA, meanwhile, warned the seeds are present for renewed civil war.

Thousands of ethnic Pashtuns are fleeing northern Afghanistan, claiming that anti-Taliban commanders have been inciting people to loot their homes and, in some cases, kill them, said U.N. spokesman Yusuf Hassan.

The French aid organization Doctors Without Borders issued an urgent appeal Thursday for more food aid in northern Afghanistan, saying malnutrition, mortality rates and the number of displaced people are all rising sharply.

The struggle to establish order and peace in post-Taliban Afghanistan came up against a new test when gunmen opened fire on a British patrol in the capital, Kabul, and the British returned fire, a peacekeepers’ spokesman said Thursday. It was the second such incident in less than a week.

Success in the quest for stability largely depends on whether the interim government can rein in the ethnic, tribal and personal rivalries that have riveted the Central Asian nation of 24 million people for more than two decades.

The cohesion of the government itself came into question this week after interim Prime Minister Hamid Karzai accused senior members of his own administration of assassinating aviation minister Abdul Rahman during a riot last week among would-be Islamic pilgrims at the Kabul airport.

On Wednesday, Foreign Minister Abdullah publicly disavowed Karzai’s version of events, saying the angry mob, not government conspirators, killed Rahman. Both Karzai and Abdullah have sought to quell media speculation of a rift inside the government.

In recent days about 20,000 Afghans, mostly people fleeing drought, hunger and ethnic strife, have fled to Chaman, a crossing point on the Afghan-Pakistani border, said Hassan, the U.N. spokesman.

The Pentagon acknowledged Thursday that U.S. forces mistakenly killed 16 Afghan villagers in a raid north of Kandahar last month but Defense Secretary Donald Rumsfeld denied the operation had been an error, saying Americans were attacking what they believed was an enemy camp.