The UN's cultural organisation on Thursday condemned the killing of Nabil Hasan al-Quaety, a Yemeni journalist who contributed to AFP, in the southern city of Aden this week.

"I call on all parties to respect their obligation under the Geneva Conventions to protect journalists," the UN Educational, Scientific and Cultural Organization (UNESCO) director general Audrey Azoulay said in a statement.

"Brave reporters like Nabil Hassan carry out important work keeping people in Yemen informed and documenting the extreme conditions their country is experiencing. They must be offered every possible protection."

The 34-year-old videographer and photographer, who also worked for other major news organisations in the region, was shot in his car on Tuesday by unknown assailants shortly after leaving his home in Aden.

A security source told AFP the armed men had escaped.

Yemen's government and the secessionist Southern Transitional Council (STC) both condemned the killing.

Quaety, who also went by the name Nabil Hasan, began working with AFP in 2015. He was married with three children and had a fourth on the way.

In 2016, he was a finalist in Britain's Rory Peck Award for his work covering the long conflict that pits the government against the Huthi rebels, with an entry the judges described as "rare and outstanding".

In January 2019, Quaety survived a deadly Huthi drone attack on Yemen's largest airbase, Al-Anad, north of Aden, during a military parade he was covering.

Another AFP contributor in Yemen, photographer and videographer Abdullah al-Qadry, was killed in 2018 during shelling while on assignment for Yemen's Belqees television.

Yemen lies in 167th position out of 180 countries on Reporters Without Borders' world press freedom index.