The US will deploy “defensive” troops to Saudi Arabia amid heightening tensions in the region after oil facilities in the country were attacked last Saturday, the Defense Department said Friday night.

Secretary of Defense Mark Esper made the announcement at the Pentagon, saying the military resources will focus on “air and missile defense.”

“The president has approved the deployment of US forces, which will be defensive in nature,” Esper said in brief remarks to reporters after meeting with the president earlier in the day.

Gen. Joseph Dunford, the chairman of the Joint Chiefs of Staff, described the deployment as “moderate” and said the number of troops would likely not exceed 1,000.

Esper said a number of actions taken by Iran in the region — especially the alleged attack on Saudi oil facilities last Saturday — led both Saudi Arabia and the United Arab Emirates to request international military support.

“The Iranianan regime is waging a deliberate campaign to destabilize the Middle East and impose costs on the international economy,” Esper said.

“The attack on September 14th against Saudi Arabian oil facilities represents a dramatic escalation of Iranian aggression,” he added.

Both the US and Saudi Arabia blame Iran for the attack on the oil facilities, but Iran has denied launching it.