DUBAI (Reuters) - Eleven headless bodies have been dumped in a nature reserve in the southern Yemeni port city of Aden, a local news website reported on Wednesday.

The Aden al-Ghad news website quoted a security source in the city as saying that the male bodies were found on Tuesday evening in the al-Hiswa reserve, west of Aden.

It was not immediately clear who killed the men and why, but Aden al-Ghad said the condition of the bodies suggested they had been dumped there more than a month ago.

Yemen’s second largest city has been suffering from lawlessness, as armed groups including Islamic State and al Qaeda continue to maintain influence nearly a year and-a-half after supporters of President Abd-Rabbu Mansour Hadi, backed by Arab coalition troops, drove the Iran-aligned Houthis out.

Hadi’s government is struggling to restore security to the city of one million. The southern port city is under the control of the internationally recognized government in exile in Saudi Arabia.

Last Saturday, a suicide bomber killed 50 soldiers when he blew himself up at a military base in the city in the latest of a series of attacks claimed by Islamic State.

At least 10,000 people have been killed in the 20-month conflict, which has unleashed a humanitarian crisis on the impoverished country.