Saudi shells have hit an international humanitarian aid office in northern Yemen, killing five Ethiopian refugees and wounding ten.

Artillery fire and air strikes hit the town of Maydee along Yemen's border with Saudi Arabia in Hajja province, a stronghold of the Iran-allied Houthi militia that a Saudi-led Arab alliance has been bombing for eight weeks, local officials said.

Saudi forces and Houthi militiamen also exchanged heavy artillery and rocket fire, and Arab airstrikes hit Houthi positions inside Yemen, violence that may complicate plans for UN-backed peace talks set for next week in Geneva.

Tribal sources along the Saudi-Yemeni border said that more than 15 Houthi fighters and at least one Saudi officer were killed in intense clashes on Wednesday.

Residents and local fighters opposing the Houthis said airstrikes also hit a southern air base controlled by the militia and their positions outside the city of Aden on Thursday.

Tribal and militia fighters in Yemen's south support the Arab campaign and back president Abd-Rabbu Mansour Hadi, who lives in exile with his government in Saudi Arabia.