WASHINGTON (Reuters) - The Trump administration notified Congress last week that it soon planned to begin delivering precision-guided munitions to Saudi Arabia under a 2015 weapons deal, congressional officials said on Tuesday.

Saudi Arabia's King Salman bin Abdulaziz Al Saud (R) and U.S. President Donald Trump (L) react to applause after signing a joint security agreement at the Royal Court in Riyadh, Saudi Arabia May 20, 2017. REUTERS/Jonathan Ernst

The Senate voted 53 to 47 to narrowly defeat legislation that sought to block portions of a new, separate arms sale to Saudi Arabia, agreed during a visit there by President Donald Trump in May.

Arms sales to Riyadh have become increasingly contentious in the U.S. Congress, where some lawmakers object that American weapons have contributed to widespread civilian casualties in a Saudi-led military campaign in Yemen.

Republican Trump’s predecessor Barack Obama, a Democrat, suspended the planned sale of precision-guided munitions in December because of concerns over civilian casualties in Yemen, where the civil war pits Iran-allied Houthi rebels against the government backed by a Saudi-led Arab coalition.

Trump, however, has said he wants to encourage weapons sales as a way to create jobs in the United States.

Senator Ben Cardin, the top Democrat on the Senate Foreign Relations Committee, said the administration had notified Congress about the start of deliveries on the 2015 sale. He said in a statement that Trump’s decision was another reason for the Senate to disapprove the new sale.

“We need to send a message to both the Trump Administration and the Saudis to work much harder to avoid civilian casualties, expedite humanitarian relief, and push for a peaceful end to the war through a negotiated political settlement,” Cardin said.

Republicans control both chambers of Congress.

A senior congressional aide, speaking on condition of anonymity, said the notification was received last Thursday. The decision to move ahead with deliveries was first reported by Bloomberg.

The 2015 sale included more than 8,000 Laser Guided Bombs for the Royal Saudi Air Force. The package also includes more than 10,000 general purpose bombs, and more than 5,000 tail kits used to inexpensively convert “dumb” bombs into laser or GPS-guided weapons.

Some of the weapons systems included in the sale were made by Raytheon Co and Boeing Co.

The arms deal announced in May was for $110 billion, with options running as high as $350 billion over 10 years.

Tuesday’s Senate vote, which would block about $500 million of that sale, including precision-guided munitions and other offensive weapons, coincides with Saudi Foreign Minister Adel al-Jubeir meeting with U.S. Secretary of State Rex Tillerson and other officials in Washington.