“The United States is locked and loaded.”
He tweeted an assault might come “not so soon at all” – less than 24 hours after warning Russia to “get ready” for an attack on its ally.
Israel has yet to comment on the strike, while the U.S. and France have denied involvement.
The White House announced on Monday that the U.S. is expelling 60 Russian officials and ordering the closure of the Russian consulate in Seattle.
Russian and Syrian warplanes continued hammering the devastated Syrian rebel enclave of eastern Ghouta on Monday.
The sanctions target 271 employees of a Syrian research facility that the US believes develops chemical weapons.