According to Politico:
Just days after Donald Trump Jr. suggested he be given a Pulitzer Prize, Cernovich tweeted, “Sources telling me U.S. attack in Syria planned for tonight, we must stop! #NoMoreWar,” at 7:40 pm Eastern time, an hour and a half before NBC News broke the news of the airstrike.
So at 4:40pm PDT or 7:40pm EDT a Trump supporter with 247,000 followers tweeted:
At 8:40pm EDT or 3:40am Syrian time, tomahawk missiles hit a Syrian military airport:
7:40 p.m.
Fifty-nine Tomahawk missiles were launched from Navy destroyers in the eastern Mediterranean. All 59 hit their target.
8:30 p.m.
Notification of foreign leaders and congressional leadership began. The vice president called several congressional leaders and began calling some foreign leaders. The secretary of State, the secretary of Defense, national security adviser and others were also involved in making those phone calls to...heads of government, defense ministers and congressional leaders.
Between 8:30 - 8:40 p.m.
The first impacts began on the ground. The president informed President Xi that strikes were occurring as their dinner concluded. All along, the national security team continues to monitor the event, the situations.
I suppose it is possible his sources were in Russia, but if they were in the US this sounds like treason.
I’m sure the Trump administration will investigate right away how their operation was compromised.