A suicide bomber has killed at least eight soldiers in an attack on a military camp in Yemen's southern city of Zinjibar at dawn, according to local official and residents.

The bomber, wearing a military uniform, on Friday struck Najda Camp in the Abyan provincial capital along the coast from second city Aden where the government has its headquarters.

He failed to get through the gate and heavy exchanges of gunfire ensued as other attackers tried to penetrate the base.

Residents said they heard a loud explosion at dawn in Zinjibar. The bomber was suspected to be an al-Qaeda member, the local official said.

Yemen has been embroiled in civil war since March 2015 between the internationally recognised government of President Abd-Rabbu Mansour Hadi, which is backed by an Arab coalition assembled by Saudi Arabia and Iran-allied Houthi rebels.

US inquiry urged

Separately, Human Rights Watch, the US-based international organisation, urged the US government on Friday to open an investigation into the deaths of civilians, including children, in a US assault in Yemen.

The January 29 raid in Yakla, in central Yemen, also left one US Navy Seal dead and six American soldiers wounded.

A military aircraft suffered a hard landing and had to be destroyed in the assault, which occurred just days after US President Donald Trump's inauguration.

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Human Rights Watch said that at least nine children were among the slain civilians. A hospital director also said that the wounded had no access to medical care for hours.

Nadim Houry, HRW terrorism director, said the US needs to "go a step further and provide a full accounting of possible laws-of-war violations".

At least 10,000 people have died in the mostly stalemated conflict, which has prompted a humanitarian and hunger crisis in the already poor Arabian Peninsula country.