RIYADH — Two Saudi soldiers have been killed in a clash with unidentified gunmen who fired on them from across the border with Yemen, the interior ministry said Thursday, April 10.

A border guard patrol in the southwestern province of Asir “came under heavy gunfire on Wednesday morning from unknown sources inside Yemeni territory,” said the ministry.

The attack triggered a gun battle which resulted in the death of sergeant Abdulrazaq al-Qhamidi and soldier Mohammed al-Qahtani, said the ministry a statement.

The Saudi authorities were coordinating with their counterparts in Yemen to investigate the attack.

The kingdom’s long and porous border with Yemen is frequently crossed by smugglers as well as Islamists seeking to join al-Qaeda militants in the impoverished Arabian Peninsula nation.