DUBAI — The UN envoy to Yemen said he was “alarmed” over the escalation of violence after a drone attack by Iran-backed Houthi militants on the country’s largest airbase killed six soldiers.

In tweets posted overnight Thursday Martin Griffiths urged all parties to Yemen’s protracted conflict to exercise restraint.

The attack comes as the UN, which brokered several agreements between the Houthis and the government at talks in Sweden last month, is desperately seeking to re-launch negotiations for an end to four years of devastating conflict.

Griffiths tweeted that he was “alarmed by today’s (Thursday) escalation of violence in Yemen”.

He urged “all parties to the conflict to exercise restraint and refrain from further escalation” and to “create a conducive environment to maintain the positive momentum generated” in Sweden.

The UN was hoping last month’s talks in Sweden would help launch formal peace talks between Yemen’s warring parties.

Thursday’s attack is likely to create a new obstacle for those efforts.

In Sweden, the warring sides agreed truce deals for the port of Hodeida and Taez.

Condemning the attack, UAE Minister of State for Foreign Affairs Anwar Gargash tweeted: “The murderous drone attack tells you everything you need about the Houthis. Peace negotiations are a tactic to them, not a commitment.” “464 ceasefire violations, 36 killed & 318 wounded since (Sweden) agreement. The international community must increase pressure,” Gargash said, blaming the Houthis for the slow progress of peace efforts. — AFP