Human Rights Watch has accused the Saudi-led coalition fighting in Yemen of committing war crimes, saying its air raids killed 39 civilians, including 26 children, in two months.

The rights group says five air raids that hit four family homes and a grocery store were carried out either deliberately or recklessly, causing indiscriminate loss of civilian lives in violation of the laws of war.

"Such attacks carried out deliberately or recklessly are war crimes," HRW said in a report on Tuesday.

The coalition has repeatedly denied allegations of war crimes and says its attacks are directed against its enemy - Yemen's armed Houthi group - and not civilians.

Yemen has been torn by a civil war in which Yemen's internationally recognised government, backed by a coalition supported by the United States and Britain, is trying to roll back the Iran-aligned Houthi fighters who control most of northern Yemen, including the capital Sanaa.

READ MORE: Saudi coalition kills hundreds of Yemenis in 2017

"The Saudi-led coalition's repeated promises to conduct its air strikes lawfully are not sparing Yemeni children from unlawful attacks," Sarah Leah Whitson, Middle East director at HRW, said in a statement.

"This underscores the need for the United Nations to immediately return the coalition to its annual 'list of shame' for violations against children in armed conflict."

On August 4, coalition aircraft struck a home in Saada, killing nine members of one family, including six children, ages three to 12.

On July 3, an air raid killed eight members of the same family in Taiz province, including the wife and eight-year-old daughter, the organisation said.

HRW said it interviewed nine family members and witnesses to five air raids that occurred between June 9 and August 4 and did not detect any potential military targets in the vicinity.

The war has killed more than 10,000 people, displaced more than three million and ruined much of the impoverished country's infrastructure.

The Saudi-led coalition was formed in 2015 to fight the Houthi group and army troops allied with them who have fired missiles into the kingdom.

HRW called on the UN Security Council to launch an international investigation into the abuses at its September session.

On Monday, the UN said it had verified 5,144 civilian deaths in the war in Yemen, mainly from air raids by a Saudi-led coalition, and an international investigation is urgently needed.