Talks aimed at ending the war in Yemen are due to begin in Geneva on Monday, amid worsening humanitarian situation in the country.
The UN-led talks are thrown in doubt as there is uncertainty whether rebel Houthi negotiators will attend, with reports saying that Shia rebels, who control much of Yemen, missed a flight to Geneva.
Associated Press quoting airport officials reported that a plane meant to carry Shia Houthi rebels and their allies to talks left Sanaa International Airport without the delegates on board.
The talks are slated to be the first substantive meetings by all parties involved in the conflict.
The delegation representing the government of exiled President Abd-Rabbu Mansour Hadi arrived in Geneva Saturday morning, an official from the presidency said.
A coalition of 13 aid organizations has called for a permanent ceasefire as the conflict has affected 80 percent of the population or around 20 million people.
Dwindling basic supplies
Al Jazeera has been to the southern city of Taiz, where a Houthi siege has strangled the supply of the most basic necessities.
Most government services have been cut because of the fighting around the city.
Schools are shut, power is down, and supplies are running desperately low.
The relief groups have also called for the lifting of an air and sea blockade imposed by the Saudi-led coalition that launched a bombing campaign in late March in support of exiled President Hadi.
A five-day ceasefire last month allowed aid agencies to reach civilians caught in the fighting but UN efforts to extend the truce failed.
Meanwhile, warplanes from the coalition led by Saudi Arabia struck rebel positions in the central province of Dhamar, as well as air defense positions of allied troops loyal to former president Ali Abdullah Saleh, witnesses said.
Rebel positions in their northern Saada stronghold were also hit, they added.
A wave of intensive overnight air strikes targeted arms depots around the capital and residences of people close to Saleh, including his brother's home, south of Sanaa, witnesses said.
PHOTO CAPTION
Damage is seen at the Yemeni army's main headquarters after it was hit by a Saudi-led air strike in Sanaa, June 7, 2015.
Aljazeera