The Al Jazeera Media Network has called for the immediate release of an Al Jazeera Arabic news team who are believed to have been kidnapped in the city of Taiz in southern Yemen.

Al Jazeera Arabic correspondent Hamdi al-Bokari and his crew, Abdulaziz al-Sabri and Moneer al-Sabai, were last seen on Monday night.

"We call for the immediate release of our colleagues Hamdi al-Bokari, Abdulaziz al-Sabri and Moneer al-Sabai," said Mostefa Souag, the acting director general of Al Jazeera Media Network.

"They were covering events in the besieged city of Taiz, reporting on the human cost to the conflict. Our colleagues were simply doing their job of reporting the story and informing the world on what is taking place in Yemen."

Hamdi al-Bokari, a Yemeni national, was last seen around 10pm on Monday in the centre of the war-torn city, according to a statement by Al Jazeera Arabic.

The news channel said in the statement on Thursday that there were "indications that he had been kidnapped by unknown persons".

Bokari has worked for Al Jazeera Arabic since 2006.

Strategic gateway

"Al Jazeera holds their abductors responsible for their safety and security," Souag said. "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."

Doctors Without Borders (MSF) was allowed to enter the city to supply hospitals for the first time in five months. Heavy fighting and a lack of medical supplies have caused many hospitals and clinics to close .

Two MSF trucks filled with medical supplies entered Taiz to re-supply hospitals that were struggling to cope with a large number of wounded people.

Taiz has become a flashpoint in the ongoing war between Iran-allied Houthi fighters, who control the capital Sanaa, and forces loyal to President Abd-Rabbu Mansour Hadi.

Hadi loyalists control Aden and much of the country's south with the backing of an Arab coalition led by Saudi Arabia.

Taiz is seen as a strategic gateway between Sanaa and the south.