John Bolton, Trump's national security advisor who advocated attacking Iran before taking his position, announced late Sunday that the USS Abraham Lincoln Carrier Strike Group would sail to unspecified waters in the vicinity of Iran.

The deployment is aimed at sending "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," Bolton said.

"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 USS Abraham Lincoln has previously been deployed to the Gulf, including during the 2003 invasion of Iraq, and was the scene of president George W. Bush's later notorious victory speech in front of a banner that read "Mission Accomplished."

The Pentagon had already announced with little fanfare last month that the USS Abraham Lincoln and the rest of its strike group had headed on a "regularly scheduled deployment" out of its base in Norfolk, Virginia.

But Bolton gave the deployment a new urgency as he said that it was in response to "a number of troubling and escalatory indications and warnings" by Iran.

Secretary of State Mike Pompeo told reporters he could not elaborate on what those indications were, but said they were separate from a violent flare-up between Israel and Hamas, the Iranian-backed Islamist militant group that runs the Gaza Strip.

- Based on intelligence, or politics? -

Mark Dubowitz, chief executive of the Foundation for Defense of Democracies, which advocates a hard line on Iran, said he had heard of a "spike" in intelligence in recent days about planned attacks.

He believed Iran had given the green-light to the missiles out of Gaza by Hamas as allied movement Islamic Jihad.

The strikes sought "to tie down Israeli forces and create a crisis to distract the US and Israel from IRGC plans elsewhere," he said, referring to Iran's elite Revolutionary Guards.

Other observers were much more skeptical, believing that Bolton had seized on a routine deployment as a way to pile pressure on Iran.

The statement came almost a year to the date after Trump pulled the United States out of a multinational accord under which Tehran drastically scaled back its sensitive nuclear work.

"I think this is manufactured by Bolton to try to justify the administration's very harsh policy toward Iran despite the fact that Iran has been complying with the nuclear deal," said Barbara Slavin, the director of the Future of Iran Initiative at the Atlantic Council think tank.

"Given Bolton's record," she said, "I wouldn't put it past him to try to manufacture a crisis here."

UN inspectors say that Iran has been in compliance with the nuclear deal, which is still backed by European powers as well as Trump's Democratic rivals seeking to unseat him next year.

But Iranians have voiced frustration that they have not seen a promised economic boon, with Trump instead slapping sweeping sanctions on the country.

In recent weeks, the Trump administration has hit even harder, moving to ban all countries from buying Iran's oil, its top export, and declaring the Revolutionary Guards to be a terrorist group -- the first such designation of a unit of a foreign government.

Iranian President Hassan Rouhani, considered a moderate inside the clerical regime, may announce "retaliatory measures" on Wednesday on the anniversary of the US pullout, the semi-official ISNA news agency said.