The United States is sending 1,000 additional troops to the Middle East, amid rising tensions between the United States and Iran.

According to Associated Press (AP), U.S. officials say the Pentagon is sending about 1,000 additional American troops to the Middle East, as commanders try to bolster security for forces and allies in the region from what the U.S. authorities say is a growing threat from Iran.

Officials say the deployment includes security forces and troops for additional surveillance and intelligence gathering in the region.

The troops are part of a broader military package of options that were initially laid out to U.S. leaders late last month, totaling as much as 10,000 forces, Patriot missile batteries, aircraft and ships.

ABC News says the U.S. has already accelerated the deployment to the Middle East of the USS Abraham Lincoln aircraft carrier strike group and sent B-52 bombers after what it said were credible threats by Iran against U.S. forces and interests in the region. Since then, the U.S. has sent an additional 1,500 troops and increased defensive capabilities to continue to help deter Iran.

The latest decision comes as Secretary of State Mike Pompeo and other top officials reach out to leaders in Asia and Europe to convince them that Iran was behind alleged attacks on shipping along a Middle East oil route.

The United States has blamed Iran for attacking a Japanese tanker owned by Kokuka Sangyo Co and another tanker, the Norwegian-owned Front Altair, on June 13, but Tehran has denied the allegations.

U.S. Central Command said the two vessels were hit by a limpet mine, which is attached to boats below the waterline using magnets.

The Japanese owner of a tanker attacked in the Gulf of Oman, however, said on Friday (June 14) the vessel was struck by a projectile and not by a mine, which is what U.S. officials assessed as the source of the blast.

“We received reports that something flew towards the ship,” Yutaka Katada, president of Kokuka Sangyo, said at a press conference on June 14, according to CNBC.  “I do not think there was a time bomb or an object attached to the side of the ship,” he said, adding that a projectile landed above the waterline.