The Saudi-led coalition fighting Houthi rebels killed a six-member family in an air strike on the family's house in the Yemeni Red Sea port city of Mokha on Sunday evening, a medic and security official said.

"Doctor Molok Mahis, director of maternal and childhood center, a non-governmental organization, was critically injured in the air strike on her home in Mokha and she is being now treated at the intensive care in the hospital," the medic said by phone.

"Her leg was amputated in the air strike and six members of her family were killed," the medic said.

The security official in the port city confirmed that all six members of social activist Mahis were killed in one of the evening air strike that flattened her house to the ground.

This is the latest in a series of air strikes hitting Yemeni civilians since the war began in 2015.

Two weeks ago, Yemeni government forces backed by the coalition of Gulf Arab troops and warplanes led by Saudi Arabia stormed the coast city from the northwestern part and paved the way for an advance on neighboring main port city of Hodeidah.

However, the battles have since intensified and trapped thousands of civilian residents in the city, as well as hampered the humanitarian operation to import vital food and fuel supplies, according to a recent statement by the United Nations.

On Friday, the Geneva-based UN human rights office (OHCHR) said that it received extremely worrying reports suggesting civilians and civilian objects have been targeted over the past two weeks in the southwestern port city of Al Mokha in Taiz governorate.

Reports received by UN also show that more than 200 houses have been either partially damaged or completely destroyed by air strikes in the past two weeks.

Since March 2015, the coalition has been fighting the Houthi rebels, who have seized control of most of northern Yemen including the capital Sanaa, to restore power to the expelled but internationally recognized government of President Abd-Rabbu Mansour Hadi.

The war and airstrikes have killed more than 10,000 people, half of them civilians, and displaced over two millions, according to humanitarian agencies.