The Russian Embassy in the US tweeted a cryptic-yet-hostile message Friday threatening the F-35 stealth fighter and mocking the US Air Force's top officer.

The tweet told the US to "remember Vietnam" and was accompanied by propaganda footage of Soviet surface-to-air missiles blasting fighter jets out of the sky.

The tweet was an apparent reply to a recent speech by Air Force chief of staff Gen. David Goldfein, who touted the F-35's ability to penetrate Chinese and Russian defenses.

The Russian Embassy in the US took aim at America's F-35 stealth fighters on Friday in a threatening message apparently tweeted in response to an earlier speech by the chief of staff of the US Air Force.

"'If a Russia... ever was to see an F-35 inside its airspace', we would love to send Chief of Staff of the [US Air Force] Gen. David L. Goldfein 'message with two words' — 'remember Vietnam,'" the tweet read, adding, "'An F-35 will never be alone.'"

The cryptic message was accompanied by Vietnam War propaganda footage of Soviet missiles shooting down fighter jets to an operatic score, the lyrics for which reportedly were "you can’t take away the sky from Vietnam" and "you can’t take the sun away from Vietnam," according to Foxtrot Alpha, which first reported this story.

The US lost 1,737 aircraft in the skies above Vietnam, Cambodia, and Laos during the Vietnam War, according to Air Force Times.

—Russia in USA 🇷🇺 (@RusEmbUSA) February 22, 2019

The message is weird even for the Russian embassy, which has a history of posting similar tweeting tweets.

The tweet was a play on the words Goldfein had spoken during a talk at the Brookings Institution last Wednesday. He boasted about the successes of the F-35 during a recent air-combat exercise.

Read more: US Air Force F-35s wrecked their enemies in mock air combat — even the new pilots were racking up kills against simulated near-peer threats

"If a China or a Russia or another adversary on the globe ever were to see a F-35 inside their airspace," Goldfein said. "I would love to send them all messages with two words — 'we're here.'"

"It's not 'I'm here,'" he added. "An F-35 will never be alone."

Emphasizing the importance of penetrating capabilities, Goldfein described the F-35 as a "quarterback" capable of relaying information to multiple force assets operating in enemy airspace, according to the South China Morning Post.

"We're here ... We've been watching you. We know what's going on, and we've already penetrated whatever the defenses you think you have," Goldfein said.

The Russians are apparently less than pleased with thought of US fighter jets operating in their airspace, thus the hostile tweet.