The United Nations envoy to Yemen will return to Saudi Arabia to meet with members of the exiled Yemeni government after it pulled out of U.N.-mediated peace talks with its Houthi adversaries, the U.N. press office said on Monday.

In the latest Saudi air raid, at least one civilian sustained injuries after warplanes targeted Rizih district in the northwestern province of Sa’ada.

The escalation comes as the exiled government backed out of a proposed new round of UN-brokered peace talks, insisting that rebels should withdraw from captured territory.

Earlier this year, Hadi fled to Saudi Arabia, which began leading a coalition bombing campaign against the Houthis.

Yemen’s conflict pits an array of forces against the Houthi rebels, who are allied with security forces loyal to former President Ali Abdullah Saleh. More than 4,500 people have been killed since the beginning of the war in March.

Saudi Arabia has long accused Iran of arming and financing Shiite Houthi fighters against Yemeni President Abd-Rabbu Mansour Hadi, an accusation strongly rejected by Tehran.

“There will be no participation in any meeting until the coup-plotting militia [Houthis] announces an unconditional acceptance of the worldwide resolution 2216”, a presidential statement said.

The ground offensive marks the first significant attempt by the coalition to control the province, which has seen the most airstrikes in the country since the Saudi offensive began.

The humanitarian group Oxfam said Friday that British weapons supplied to the Saudi-led forces were escalating the crisis and might be in breach of laws prohibiting arms sales to conflict zones. This remarkable arrangement starkly underscores the cynical character of the USA claims to be fighting “terrorism” in the Middle East.

Out of their Al-Aber base in nearby Hadramawt province, government troops have moved towards four rebel footholds in northwest Marib, on the route to Sanaa.

On Saturday night, a suspected US drone strike killed at least five al-Qaida fighters gathered inside a military base outside the eastern coastal city of Mukalla, local security officials said.