A Saudi citizen was killed in shelling fired across the border from Yemen into the southwest of Saudi Arabia on Sunday, the official SPA news agency reported.

A shell fell on a house around dawn in Najran province, civil defence department spokesman Ali bin Omair al-Shahran was quoted as saying.

SPA did not say who carried out the shelling, but Houthi rebels and forces loyal to former Yemeni president Ali Abdullah Saleh have carried out similar attacks since war erupted in Yemen four months ago.

A Saudi-led Arab alliance launched a military campaign on March 26 to end Houthi control over much of Yemen and to return President Abd-Rabbu Mansour Hadi from exile.