An American worker for the United Nations has been kidnapped in Pakistan, by people whose fists are apparently tightly clenched.

QUETTA, Pakistan – Authorities searched for an American U.N. worker kidnapped Monday in southwestern Pakistan in an attack that underscored the security threats in the country as it battles al-Qaida militants.

The government called the abduction a “dastardly terrorist act,” but police said it was not clear whether Islamist militants, criminals seeking a ransom payment or members of a regional separatist group were responsible.

Gunmen seized John Solecki, head of the U.N. refugee office in the city of Quetta, as he traveled to work Monday morning, and shot and killed his driver, U.N. and Pakistani officials said.

(Hat tip: Thanos.)