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

The news network said on Thursday that Hamdi al-Bukari, who had been covering the intense Taiz fighting that started in April, went missing on Monday night.

It called for the release of al-Bukari, and said it held the kidnappers responsible for his safety. It did not name the group behind his alleged abduction.

In Taiz, Shiite rebels known as Houthis have been battling local fighters, who include ultraconservatives and pro-government forces.

Several journalists have been killed, detained or expelled during Yemen's war. In September 2014 Houthis took control of the capital, prompting a Saudi-led military campaign in support of the government.