An American military official said that the airstrike had been called in by Afghan and American forces who were under fire from Taliban fighters. “The operation was requested by the Afghans and approved by the Afghans,” the official said.

It is too early to tell whether life in Kabul will permanently change. Often after similar attacks, enough time passes that the worst is forgotten and a semblance of normality returns. But by Saturday morning, practically every international organization in Afghanistan, including the United Nations, was re-examining its safety policies.

Most have tightened security, clamping down on the number of restaurants and guesthouses their staff members can visit and limiting approved social activities. United Nations officials, meeting privately, said they would also review approved locations. Still, senior officials vowed not to adopt a bunker mentality in response to the attack, which claimed the lives of four of its personnel, including two women from the United Nations Children’s Fund.

“Not ducking under our covers is not the same as being out in the open and living in Afghanistan like we do everywhere else in the world,” said a European official, who asked not to be identified while discussing security precautions. “There are dinners I think people are probably going to skip. How much do you lose? Can we measure that? I don’t know.”

News organizations, too, are likely to endure temporary restrictions on social events, at least until it becomes clearer whether the attack was an isolated episode or the beginning of a new reality for foreigners living in Kabul. That, in some respects, is most worrisome to many involved in the worlds of diplomacy, aid and the media. The more such attacks occur, the less free they are to interact with the population they work with.

Restrictive measures have already been in place at a number of embassies in Kabul, including those of the United States and Britain. Their security requirements often keep diplomats from leaving their heavily fortified compounds, even to visit programs they are funding. The attack in some respects vindicates a policy that has been criticized for being too cautious.