SANAA, Yemen — A group of American embassy staffers came under attack when a bomb was thrown into the back of their vehicle outside a restaurant in Yemen’s capital, U.S. and Yemeni officials said Thursday.

No one was hurt in the attack Wednesday evening in Hadda, a commercial district in the capital, a Yemeni security official and two U.S. officials in Washington said. The Yemeni official said a number of suspects have been arrested, without elaborating. A Yemeni newspaper close to the government said a 28-year-old Jordanian had been arrested.

An explosive device was thrown into the bed of the U.S. Embassy pickup truck outside the restaurant, and the blast disabled the vehicle, one of the U.S. officials said, adding that the embassy believes it was "likely" an attempt to target U.S. interests. The officials spoke on condition of anonymity because they were not authorized to talk to the press.

The U.S. Embassy in Sanaa said in a statement on its website that "foreign residents … were targeted for attack" Wednesday, but it gave no further detail. It urged Americans in the country "to remain vigilant" and avoid areas where attacks have occurred.

It was not immediately known whether the attack was linked to al-Qaida militants in the country. Al-Qaida’s affiliate in Yemen has carried out a number of attacks against foreign embassy staffers — most recently in October when militants fired a rocket at a British Embassy vehicle carrying four officials and the deputy chief of mission. One staffer and three bystanders were wounded.

Al-Qaida fighters have also carried out direct attacks on the U.S. Embassy in Sanaa in the past.

The United States has dramatically stepped up counterterrorism aid to Yemen’s government to fight al-Qaida, which has claimed responsibility for an attempt last Christmas Eve to blow up a passenger jet over U.S. soil and an attempt earlier this year to mail bombs to Chicago-area synagogues.

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AP correspondent Matthew Lee in Washington contributed to this report.