ADEN (Reuters) - Medecins Sans Frontieres has suspended work at its hospital in the Yemen port city of Aden after the kidnapping and killing of one of its patients, the medical relief organization said on Wednesday.

Aden, in southern Yemen, falls under the control of president Abd-Rabbu Mansour Hadi, backed by a Saudi-led military coalition, while Iran-aligned Houthi forces control the capital Sanaa in the roughly four year war that has killed tens of thousands of people.

“We are worried by the deterioration of security in #Aden and its consequences on our medical activities, for both patients and staff whose lives are endangered by these incidents,” the organization said on its Twitter account.

MSF said the patient was abducted on Tuesday and later found dead. It did not provide further details on the identity of the patient or why they were targeted.

The United Nations has in recent months struggled to implement a troop withdrawal in the strategic port city of Hodeidah, a confidence-building measure meant to clear the way for a broader peace settlement in the war.