Yemeni security officials say an airstrike launched by a U.S. drone killed at least three suspected al-Qaida militants in a province near the Saudi border.

Tuesday's strike in the Jawf province northeast of the capital Sanaa was the fourth such attack to hit al-Qaida militants since Saturday, a higher-than-usual frequency that indicates a stepped up campaign by the Americans and their Yemeni government allies.

The security officials spoke on condition of anonymity because they were not authorized to speak to the media.

Al-Qaida in Yemen is considered among the world's most active branch of the network, having planned a series of foiled or aborted attacks on U.S. territory.

The United States rarely comments on its military role in Yemen, but has acknowledged targeting al-Qaida militants in the past.