A US-made bomb was used in a Saudi-led strike on Yemen's capital last month that killed 16 civilians, including seven children, and orphaned a young girl, Amnesty International said Friday.

The rights watchdog said its arms expert analysed remnants of the bomb recovered in Sanaa and that it "bore clear markings that matched US-made components commonly used in laser-guided air-dropped bombs".

"We can now conclusively say that the bomb that killed Buthaina's parents and siblings, and other civilians, was made in the USA," said Amnesty's Middle East research director Lynn Maalouf.

She was referring to five-year-old Buthaina Mansur who survived the attack but whose parents and five siblings were killed by the bomb. A picture of the little girl being rescued went viral.

Seventeen people were also wounded in the August 25 air strike that levelled two apartment buildings in Sanaa's southern neighbourhood of Faj Attan.

The Saudi-led coalition entered Yemen's war in 2015 in support of the government against Iran-backed Houthi rebels, who seized Sanaa the previous year and control it to this day in alliance with forces loyal to ex-President Ali Abdullah Saleh.

Children, according to UNICEF, account for at least 1,712 of the more than 8,500 deaths in Yemen since the coalition intervened in Yemen.

A day after the deadly air strike, the coalition admitted responsibility for the raid, describing it as a "technical mistake".

The coalition has been repeatedly accused of killing civilians during its air strikes on Yemen.

In December 2016, the US administration under then president Barack Obama blocked the transfer of precision-guided bomb kits to Riyadh.

A senior administration official said the move reflected "strong concerns with the flaws in the coalition's targeting practices" and its overall conduct of the Yemen air war.

US President Donald Trump has stepped up military support to Riyadh since taking over from Obama.

The US and Saudi Arabia in May announced an arms deal worth almost $110 billion, described as the largest in US history.

The head of the Norwegian Refugee Council on Friday urged a return to diplomacy for the sake of Yemeni civilians.

"Privileged neighbours and regional powers bring fuel to the fire, while Yemeni civilians pay the price for the war," NRC head Jan Egeland said on the sidelines of the UN General Assembly in New York.