Turkish soldiers patrol along a wall on the border line between Turkey and Syria, in the Turkish border town of Ceylanpinar, in Sanliurfa province, Oct. 29, 2019. Photo: Reuters / Kemal Aslan.

A British relief worker with an Islamic aid group was seized on Monday night by militant group Hayat Tahrir al-Sham (HTS) in northwest Syria, according to the aid group, the Syrian Observatory for Human Rights and activists in the area.

HTS is a jihadist group that controls parts of Syria’s northwest, a rebel-held area still at war with Damascus. Formerly known as the Nusra Front, it has been designated a terrorist group by the United States, Turkey and others.

Tauqir Sharif, a relief worker with the group Live Updates From Syria (LUFS), was captured in Atmeh, a town north of Idlib province near the Turkish border, according to activists in the area.

“LUFS team member…was kidnapped tonight around 9.30PM by HTS and taken to an unknown location,” the group wrote in an Instagram post.

On its Facebook page, LUFS describes itself as a Muslim Western charity supporting displaced people in Syria.

The motive for his seizure was not immediately clear.

Sharif has been living in Syria since 2013, according to a LUFS post on YouTube.

Syria’s northwest is home to a mix of Islamist militant and opposition groups, many of which have fled other parts of Syria as President Bashar al-Assad, with Russian backing, has seized back territory during the roughly nine-year-old war.

The area is also populated by hundreds of thousands of internally-displaced persons who rely heavily on humanitarian assistance.