ADEN, Yemen - A roadside bomb targeting a Yemeni security patrol killed three children on their way to school in the southern province of Hadramout on Sunday, the Defence Ministry said.

Separately, the Interior Ministry said on its website security forces were on alert for a potential plot by al Qaeda targeting "vital and government installations" in the southern province of Dalea. It gave no further details but called on residents to report any "terrorist" activities.

The Defence Ministry, on its website, blamed al Qaeda insurgents for the children's deaths. A local official said the explosives were placed on a road in al-Qatn city in Hadramout.

Yemen's south is a turbulent region where secessionists are seeking to revive a southern state and where an active wing of al Qaeda has taken root.

The Islamists' footprint in the south expanded during a year of mass protest against former President Ali Abdullah Saleh. He gave way to his deputy in February under the terms of a deal crafted by Yemen's Gulf neighbours with U.S. and U.N. backing.?