A Saudi-led coalition air strike killed dozens of civilians in a northern province of Yemen on Sunday, according to residents. Thirty-six workers at a bottling plant in the province of Hajjah were reportedly killed in the strike.

Issa Ahmed, a resident of Hajjah, a province which borders Saudi Arabia, confirmed that the bottling plant was targeted by an air strike and that 36 workers were killed in the attack. More than 4,300 people have now been killed in five months of conflict in Yemen between Sunni Saudi Arabia and the Shiite Houthi rebels.

"The process of recovering bodies is finished now," he told Reuters. "The corpses of 36 workers, many of them burnt or in pieces, were pulled out after an airstrike hit the plant this morning."

Last month, Human Rights Watch confirmed that another air strike killed 65 civilians at the residences of power plant workers in the port city of Mokha. Another strike, carried out in April, on a dairy plant in the port city of Hodeida killed 35 civilians. Human rights groups have condemned the air strike campaign, with Amnesty International in a report released earlier this month saying that the Saudi-led coalition was leaving a "bloody trail of civilian death".

Elsewhere, gunmen reportedly killed Col. Abdelhakim al-Sanidi, the head of security in the key Yemeni port city of Aden, on Sunday. No group has claimed responsibility for the attack but a number of Yemeni officials believe that al-Qaeda were behind the assassination, the Associated Press reported.

The Saudi-led campaign in Yemen began in March with the aim of removing the Iranian-backed Houthi rebels from power after they ousted Yemeni President Abd Rabbuh Mansur Hadi. Members of the coalition are the majority of the Gulf State members of the Gulf Cooperation Council (GCC).

The Sunni-Arab Gulf states chose to intervene in Yemen after the removal of Hadi because of concerns about Iran's growing assertiveness and influence in the region, with the potential for their Houthi proxies consolidating power on Saudi Arabia's southern frontier.