Aircraft carrier sent to Middle East after indications Iran planned attack on US forces

The United States deployed an aircraft carrier strike group and a bomber task force to the Middle East in response to "clear indications" Iran and Iranian proxies were planning an attack on U.S. forces in the region, U.S. officials said.

Late Sunday night, the White House made the surprise announcement that the USS Abraham Lincoln and a bomber task force were being deployed in response to unspecified "troubling and escalatory indications and warnings."

A statement from national security adviser John Bolton said the deployments were intended "to send a clear and unmistakable message to the Iranian regime that any attack on United States interests or on those of our allies will be met with unrelenting force."

"The United States is not seeking war with the Iranian regime, but we are fully prepared to respond to any attack, whether by proxy, the Islamic Revolutionary Guard Corps, or regular Iranian forces," the statement continued.

U.S. officials told ABC News the deployments were in response to "clear indications" Iranian and Iranian proxy forces were preparing for a possible attack against U.S. forces on land, including in Iraq and Syria, and at sea.

On Tuesday, U.S. Central Command (CENTCOM) spokesperson Navy Capt. Bill Urban said the command "continues to track a number of credible threat streams emanating from the regime in Iran throughout the CENTCOM area of responsibility."

CENTCOM requested approval from acting Defense Secretary Patrick Shanahan to move additional assets into the region, which Shanahan approved on Sunday, one official said.

"The movement of the aircraft carrier USS Abraham Lincoln to the region was expedited and it was ordered there effective immediately," another official told ABC News.

According to CENTCOM, the bomber task force that will deploy to the region consists of Air Force B-52s.

Shanahan called the move, on Twitter, a "prudent repositioning of assets in response to indications of a credible threat by Iranian regime forces."

"We call on the Iranian regime to cease all provocation," he said. "We will hold the Iranian regime accountable for any attack on U.S. forces or our interests."

Speaking with reporters in Finland on Monday, Secretary of State Mike Pompeo said that the U.S. has a responsibility to protect American diplomats around the world, but he specifically mentioned Erbil and Baghdad in Iraq and Amman in Jordan.

"And so any time we receive threat reporting, things that raise concerns, we do everything we can both to -- do all that we can to make sure that those planned or contemplated attacks don't take place and to make sure that we've got the right security posture," Pompeo said.

The USS Abraham Lincoln, the lead ship in the Carrier Strike Group, left Norfolk, Virginia on April 1. The Navy no longer provides destinations for its carrier deployments, but the carrier likely would have had to transit through the Middle East toward its new home port of San Diego at the end of its deployment. The ship is currently in the Mediterranean Sea.

Assigned to the Lincoln carrier strike group is the Ticonderoga-class guided-missile cruiser USS Leyte Gulf and four Arleigh Burke-class guided-missile destroyers, the USS Bainbridge, USS Gonzalez, USS Mason, and USS Nitze. A Spanish frigate is also accompanying the group, but it's unclear if it will stay with the American ships as they head east.

The carrier group had planned to make a port visit in Split, Croatia which has been cancelled.

The aircraft carrier USS John Stennis operated in the Persian Gulf twice during its recent deployment, for three weeks earlier this year and a week in early April.