Acting U.S. defense chief Patrick Shanahan warned Iran against any “provocation” or threats to American forces Monday after Washington deployed a naval strike group to the region.

Shanahan said the deployment “represents a prudent repositioning of assets in response to indications of a credible threat by Iranian regime forces.”

National Security Adviser John Bolton announced Sunday the USS Abraham Lincoln Carrier Strike Group, along with a bomber task force, were being deployed to the Central Command region to send “a clear and unmistakable message” to Tehran.

The move by Washington is the latest amid a series of actions to assert pressure on Iran.

The Trump administration re-imposed sanctions on Iranian oil exports in November after the president pulled out of the 2015 Iran nuclear deal between Tehran, Washington and five other countries.

The administration also ended sanctions waivers for countries buying Iranian oil.

Secretary of State Mike Pompeo echoed similar remarks Monday, saying the deployment was “something we’ve been working on for a little while” because of escalatory actions taken by Iran.

Pompeo did not say what the escalatory actions were from Iran.

“We call on the Iranian regime to cease all provocation. We will hold the Iranian regime accountable for any attack on U.S. forces or our interests,” Shanahan tweeted.

While U.S. officials have not discussed what Iranian threat caused the deployment of a naval strike group, an Israeli official told Axios news site that Israeli intelligence passed to Washington an alleged Iranian plot to American interests in the Gulf region.

The intelligence was not specific to what the threat would be, but it was clear that it was either against a U.S. target in the Gulf or an American ally like Saudi Arabia or the United Arab Emirates, according to Axios.