SAUDI ARABIA executed three soldiers for “high treason,” the reactionary Gulf kingdom’s defence ministry confirmed on Saturday, as battle intensifies in the oil-rich Yemeni region of Marib.

The trio, identified as Mohammed bin Ahmed, Shaher bin Issa and Hamoud bin Ibrahim were found guilty of “the crime of high treason in co-operation with the enemy” in a way that threatens the kingdom and its military interests, a statement said.

It did not clarify who the three soldiers were accused of colluding with, however Saudi Arabia has a long-standing regional rivalry with Iran, which it accuses of supporting Houthi rebels who they are fighting in Yemen.

A 2014 uprising saw the Houthis overrun the capital Sanaa and much of northern Yemen, with the government of president Abdrabbuh Mansur Hadi forced to flee to Aden, which he declared the temporary capital in March 2015.

A Saudi-led coalition bombing campaign began soon after with tactical and military support from Britain, France and the US.

Investigations into potential war crimes have been instigated, with Riyadh accused of deliberately targeting infrastructure, including schools, hospitals and roads.

The United Nations has warned that Yemen is on the brink of the world’s worst famine in a century as a result of the bombing and a blockade of the port of Hodeida, which has stopped food and medical supplies from reaching the population. 

Battle has intensified with at least 53 pro-government and Houthi fighters killed over the weekend as the rebels try to seize control of Marib, the ousted government’s last significant pocket of territory in the north.

“The rebels have managed to seize a bit of territory” in the latest fighting north-west of the city, a pro-government military source said, adding that they did not threaten the city of Marib itself.

The same source said 22 government soldiers, including five officers, had been killed, along with 31 rebels.