US President Donald Trump tweeted on Wednesday morning that he has instructed the United States Navy to “shoot down and destroy” Iranian gunboats that “harass” US ships.

“I have instructed the United States Navy to shoot down and destroy any and all Iranian gunboats if they harass our ships at sea,” Trump tweeted.

Trump did not cite a specific event in his tweet or provide details. The White House had no immediate comment.

I have instructed the United States Navy to shoot down and destroy any and all Iranian gunboats if they harass our ships at sea.
— Donald J. Trump (@realDonaldTrump) April 22, 2020

Following Trump’s tweet, an Iranian armed forces spokesman said the US should focus on saving its military from the coronavirus.

“Today, instead of bullying others, the Americans should put all their efforts toward saving those members of their forces who are infected with coronavirus,” Abolfazl Shekarchi said, according to Iran’s semi-official ISNA news agency.

Trump’s comments on Wednesday came about a week after 11 vessels from the Iranian Revolutionary Guards Corps Navy came close to US ships.

Earlier on Wednesday, Iran’s Revolutionary Guard said it had put the country’s first military satellite into orbit, dramatically unveiling what experts described as a secret space programme with a surprise launch that came amid wider tensions with the US.

The launch immediately raised concerns among experts on whether the technology used could help Iran develop intercontinental ballistic missiles.

On Sunday, the Revolutionary Guard acknowledged it had a tense encounter last week with US warships in the Gulf, but alleged without offering evidence that US forces sparked the incident.

Iranian and US vessels routinely have tense encounters in the Gulf and its narrow mouth, the Strait of Hormuz, through which 20 percent of all oil passes.

Tensions between the US and Iran have escalated since Trump pulled the US out of the landmark Iran nuclear deal in 2018 and reimposed crippling sanctions.

Earlier this year, the US killed Qassem Soleimani, the head of Iran’s elite Quds Force, in a drone strike in Iraq.

Iran retaliated on January 8 with a rocket attack on Iraq’s Ain al-Assad base where US forces were stationed. No US troops were killed or faced immediate bodily injury, but more than 100 were later diagnosed with traumatic brain injury.

Iranian officials have yet to comment on Trump’s Wednesday threat.