Houthis bombed indiscriminately in Yemen's Aden: Human Rights Watch

In the deadliest such attack, on July 19 in the Dar Saad district, mortar fire killed several dozen civilians, including children, it said in a report, one of a series by the rights group on abuses committed in Yemen's four-month-old civil war.

"Pro-Houthi forces have been raining mortar shells and rockets onto populated areas of Aden with no apparent regard for the civilians remaining there," the statement quoted Ole Solvang, senior emergencies researcher, as saying.

"Houthi leaders should realize that they could face a war crimes trial for ordering or even just overseeing indiscriminate rocket attacks on civilian neighborhoods," Solvang said.

Solvang told Reuters the report had used the phrase "pro-Houthi forces" because it was impossible to say whether the assailants were Houthis or forces allied to them, such as army units loyal to former president Ali Abdullah Saleh.

Residents and witnesses said the attacks on July 19 came from Houthi forces and fighters allied to them.

Yemeni analysts say the Houthis' toughest local allies in the war are units of the country's factionalized military loyal to Saleh, who stepped down in 2012 but remains one of Yemen's most influential politicians.

No spokesman for the Houthis or for Saleh could immediately be reached for comment.

On July 19 the health ministry of Yemen's exiled government said 43 people were killed and 173 wounded in bombing by Houthis and Saleh loyalists in Dar Saad.

The Houthis shortly afterwards lost control of the city to local fighters backed by Saudi-led Arab coalition forces and by the Riyadh-based Yemeni government of exiled President Abd-Rabbu Mansour Hadi.

The Saudi-led coalition has been bombing Houthis and army forces loyal to Saleh since March 26, aiming to push them back from southern and central areas and restore Hadi's government.

The Arab forces are trying to reverse months of advances by the Houthis who swept south from their northern stronghold last year, capturing the capital Sanaa and pushing onwards to Aden.

HRW said investigation of impact sites and weapons remnants showed use of multiple rocket and mortar rounds with fragmentation effects that can cause injuries over a wide area.

"These weapons, in particular unguided rockets, are difficult to target with accuracy, and when directed toward populated areas are indiscriminate," it said.

(Reporting by William Maclean; Editing by Louise Ireland)