President Trump’s national security adviser, John Bolton, held an unusual meeting last week at CIA headquarters to discuss Iran with top intelligence officials, diplomats and military advisers, NBC News said Thursday in an exclusive report.

The network identified its main sources as “six current U.S. officials” who didn’t reveal the purpose of the April 29 meeting, but said it did not involve the intelligence that prompted the administration to send an aircraft carrier strike group and a bomber squadron to the Persian Gulf this week.

NEW: In a highly unusual move, National Security Adviser Bolton convened a meeting at CIA headquarters last week with the Trump admin.'s top intel, diplomatic and military advisers, according to 6 current US officials. https://t.co/6WOagzrZ1m

— NBC News (@NBCNews) May 9, 2019

Among those at the meeting, NBC says, were CIA Director Gina Haspel, Acting Defense Secretary Patrick Shanahan, Gen. Joe Dunford, chairman of the Joint Chiefs of Staff , Secretary of State Mike Pompeo and Director of National Intelligence Dan Coats.

“National security meetings are typically held in the White House Situation Room. The six current officials, as well as multiple former officials, said it is extremely rare for senior White House officials or Cabinet members to attend a meeting at CIA headquarters,” NBC says.

When such meetings have been held in the past, they were to “brief top officials on highly sensitive covert actions, either the results of existing operations or options for new ones,” according to former CIA and military officials, the network says.

“The U.S. has a very specific intelligence gathering capability on Iran that is only able to be reviewed at CIA headquarters,” two former officials told NBC.

Bolton is a strong advocate of “regime change” in Iran, and Democrats in Congress accuse the White House of seeking an excuse to go to war.

“I’m deeply worried that the Trump administration is leading us toward an unnecessary war with Iran,” Sen. Tim Kaine of Virginia, a member of the Senate Armed Services Committee, said on Tuesday. 

 “Yet even some critics of the administration’s hard-line Iran policy said there was good reason for the acceleration last week of moving military assets in the Persian Gulf,” NBC says, quoting a former official as saying there’s “legitimate intelligence that the Iranians are preparing to launch attacks in the region.”