Al Jazeera crew missing in Yemen

The Qatar-based al Jazeera network says it has lost contact with one of its chief correspondents and his crew - who they suspect have been kidnapped in the war-torn city of Taiz, central Yemen.

Hamdi al-Bokari, who had been covering the intense Taiz fighting that started in April, went missing on Monday night, along with Abdulaziz al-Sabri and Moneer al-Sabai.

The news network has called for their release, and said it held the kidnappers responsible for their safety.

"We call on the immediate release of our colleagues Hamdi al-Bokari, Abdulaziz al-Sabri and Moneer al-Sabai. They were covering events in the besieged city of Taiz reporting on the human cost to the conflict," said Dr Mostefa Souag, Acting Director General of al Jazeera Media Network.

"Our colleagues were simply doing their job of reporting the story and informing the world on what is taking place in Yemen. Al Jazeera holds their abductors responsible for their safety and security."

Souag further added: “It is tragic to see that in times of conflict, news organisations continue to be targeted. Journalists should have the freedom to do their work without the fear of intimidation, abduction or unlawful arrest.”

Al Jazeera added that it is in contact with related parties in Taiz to secure the release of its staff, but did not name the group believed to be behind the alleged abduction.

The Arab world's poorest country has been caught in a conflict which turned international in March 2015, when a Saudi-led coalition launched a military air campaign against Houthi rebels who had taken over the capital and seized several state institutions.

More than 5,800 people have been killed and an estimated 80 percent of the population requires humanitarian aid.

But the conflict has also proved detrimental for press workers.

Eight journalists and media staff have been killed in Yemen since the start of 2015, according to data from the Geneva-based Press Emblem Campaign (PEC).

Mohammed Rajah Shamsan, a reporter for Yemen Today TV, was killed along with three of his colleagues in an airstrike by the Saudi-led coalition in April.

Two other reporters, Abdullah Kabil of Yemen Shabab TV and Yousef Alaizry of Shuhail TV, abducted by the Houthi group on May 20, were killed during an air raid.

It is tragic to see that in times of conflict, news organisations continue to be targeted. Journalists should have the freedom to do their work without the fear of intimidation, abduction or unlawful arrest - Acting Director General of al Jazeera

Yemen's third largest city, Taiz, where Bokari has been reporting from, has been under siege for months.

Various aid groups have been calling for access into the city to provide much-needed humanitarian aid to thousands of civilians.

The situation in Taiz has rapidly deteriorated, as Houthi rebels continue to battle local fighters, who include ultra-conservatives and pro-government forces.