The United States will halt the planned sale of precision-guided weapons to Saudi Arabia, a U.S. official said, in response to concerns over Saudi military practices in the Yemeni civil war, which has claimed the lives of thousands of civilians.

The official said President Barack Obama's administration canceled the sale of air-dropped precision-guided munitions to Saudi Arabia, a key U.S. ally. "That's obviously a direct reflection of the concerns that we have about Saudi strikes that have resulted in civilian casualties," the official said.

In addition to canceling the sale of the precision-guided weapons, the U.S. will alter the way it trains Saudi air force personnel to improve their accuracy, a persistent source of concern in the Obama administration.

Air strikes are war crimes?

The decisions could further strain ties between the U.S. and Saudi Arabia at a time when the incoming administration of President-elect Donald Trump prepares to assume control of the executive branch of the U.S. government.

The United Nations human rights office said in August that the Saudi-led coalition in Yemen was responsible for about 60 percent of the 3,800 civilians killed since March 2015. Some rights groups have criticized the U.S. for supporting the Saudi war effort with weapons sales and refueling Saudi-led coalition jets. Some rights groups also say attacks by the Saudi-led coalition on clinics, factories, markets and schools amount to war crimes.

Saudi Arabia has either denied the attacks or said the presence of fighters in the targeted areas justified the strikes. Saudi Arabia has not yet responded to the latest decisions by the Obama administration.

Forensics experts gather evidence in the rubble of Forensics experts gather evidence in the rubble of a funeral hall destroyed by a deadly Saudi-led airstrike on Oct. 8, 2016, in Sanaa, Yemen. Forensics experts gather evidence in the rubble of a funeral hall destroyed by a deadly Saudi-led airstrike on Oct. 8, 2016, in Sanaa, Yemen.

Since Saudi-led coalition forces entered Yemen's civil war in March 2015, the coalition has launched thousands of airstrikes against the Houthi movement - which is allied with Iran.

More than 10,000 people have been killed in the 20-month-old war in Yemen, the poorest country in the Middle East. The war has sparked a humanitarian crisis, including chronic food shortages.