ADEN (Reuters) - A bomb exploded in a market in south-western Yemen on Monday, killing at least nine civilians, a local security official said.

At least four other people were injured in the blast in a market selling qat, a mild narcotic leaf popular among Yemenis, in the city of Qa’ataba in the northern part of Dhalea province.

It was not immediately clear who planted the bomb.

Much of the country has been gripped by lawlessness fueled by a civil war between the Saudi-backed government of President Abd-Rabbu Mansour Hadi, which controls south and eastern Yemen, and the Iran-aligned Houthis who control the north and eastern part of the country.

“The crimes being committed these days indicate that the target is to create chaos and public instability,” the provincial governor, Fadhel al-Jaadi, wrote on his Facebook page. He put the number of those killed or wounded at 20.

“These crimes are being implemented randomly, without any regard to who the victims are,” he added.