President Donald Trump on Thursday announced a White House meeting on his promised steel and aluminum tariffs and again signaled close U.S. allies will receive exemptions.

“Looking forward to 3:30 P.M. meeting today at the White House,” Trump tweeted Thursday morning. “We have to protect & build our Steel and Aluminum Industries while at the same time showing great flexibility and cooperation toward those that are real friends and treat us fairly on both trade and the military.”

White House aides said Thursday morning that details about the 3:30 p.m. meeting were still being worked out. The session was not listed on the president’s public schedule, which was released by the White House around 10:45 p.m. Wednesday, suggesting the president and his communications shop again are not on the same page.

Looking forward to 3:30 P.M. meeting today at the White House. We have to protect & build our Steel and Aluminum Industries while at the same time showing great flexibility and cooperation toward those that are real friends and treat us fairly on both trade and the military.

— Donald J. Trump (@realDonaldTrump) March 8, 2018

But there was scuttlebutt earlier this week that outgoing chief economic adviser Gary Cohn, who opposes the tariffs, was trying to get industry executives in front of Trump before he signed the documents imposing the import fee.

Watch: Ryan Says There’s a ‘Smarter’ Way to Go on Tariffs

Senior White House aides have said that Trump intends to sign those documents by the end of this week. It was unclear Thursday morning if he intended to do that at the Thursday meeting.

They also said Wednesday that Canada and Mexico likely will receive exemptions, as well as other allies. All such “carve-outs” would be ordered based on national security reasons, Press Secretary Sarah Huckabee Sanders said Wednesday.

Peter K. Navarro,  director of the White House’s Office of Trade and Manufacturing Policy, said on Fox Business News Wednesday night that the steel and tariff proclamation Trump signs “will have a clause that does not impose these tariffs immediately on Canada and Mexico,” partners the U.S. is negotiating with to revamp the North American Free Trade Agreement.

Conservative groups have criticized Trump’s proposal, warning that it could cause political peril for Republicans in the upcoming midterm elections.

“We’re deeply concerned. We’ve made it clear to the administration that imposing tariffs is an enormous mistake,” said Tim Phillips, who runs Americans for Prosperity, a conservative group funded in part by billionaire brothers Charles and David Koch. “It will undercut their political chances in what’s going to be a challenging election year.”

Kate Ackley and Toula Vlahou contributed to this report.