SANAA, Yemen: An international human rights group said on Thursday that the Saudi-led coalition's recent bombing of a packed funeral in the Yemeni capital, Sanaa, constitutes an apparent war crime.

In a damning report, the Human Rights Watch said that a disproportionate number of the victims were civilians and that remnants of munitions found at the site of the attack showed that they were American made.

Coalition warplanes launched two air strikes Saturday on the funeral hall, killing nearly 140 people and wounding at least 600. The hall was hosting funeral ceremonies for the father of the interior minister in the rebel government that controls Sanaa, and several senior military and security officials in the rebel alliance were expected to attend.

An international investigation is needed into the "atrocity," said Sarah Leah Whitson, Middle East director for the rights group.

The Shiite rebels, allied with troops loyal to a former Yemeni president, overran the capital in 2015 and forced out the internationally recognized government. The Saudi-led military coalition began attacking the rebels in March of this year. The Saudis accuse the rebels, known as Houthis, of being proxies of Shiite-led Iran.

The air campaign and ongoing ground fighting have left over 4000 civilians dead and more than 7000 wounded. The war has pushed Yemen, the Arab world's poorest nation, to the brink of famine amid an imposition of a coalition blockade.

Since the beginning of the coalition's intervention in Yemen, rights groups have documented coalition bombings that struck weddings, markets, schools, and hospitals. After the funeral hall bombing, coalition officials announced an internal investigation of the incident. The HRW statement, however, demands an independent international investigation

The group also called for both the U.S. and U.K. to immediately suspend all arms sales to Saudi Arabia. The two countries have sold the kingdom billions of dollars in weapons. But in the wake of the funeral hall bombing, a U.S. official publicly warned that American support is "not a blank check."

Elsewhere Thursday, a U.S. warship launched Tomahawk cruise missiles that destroyed three coastal radar sites in Houthi-controlled territory on Yemen's Red Sea Coast. The attacks were in retaliation for a pair of incidents this week in which missiles were fired from rebel territory at U.S. Navy ships.