Iranian authorities unveiled a new mural on a giant billboard in a central Tehran square on Sunday with a direct warning to the United States to not attempt a military strike on the country, as U.S. warships head to the region.

As many as 30,000 people could have been killed in the streets of Iran on Jan. 8 and 9 alone, two senior officials of the country’s Ministry of Health told TIME—indicating a dramatic surge in the death toll.