Secretary of State Rex Tillerson's response to the attacks on American personnel in Cuba is "weak, unacceptable and outrageous," according to Sen. Marco Rubio.

Tillerson is withdrawing most U.S. staff from Havana in light of "ongoing" mysterious attacks that have caused hearing loss and "cognitive issues" in 21 American diplomats. But Rubio wants him to expel all Cuban diplomats from the United States, and consider other punishments for Raul Castro's regime.

"The idea that Cuba knows nothing about how these attacks took place and who perpetrated them is absurd," Rubio, a Florida Republican of Cuban descent, said Friday. "Until those responsible for these attacks are brought to justice, the U.S. should immediately expel an equal number of Cuban operatives, downgrade the U.S. embassy in Havana to an interests section, and consider re-listing Cuba as a state sponsor of terrorism."

Former President Barack Obama's administration removed Cuba from the official list of terror states as a preamble to normalizing diplomatic relations with the regime. President Trump's team maintained most of the Obama-era policy. A string of attacks on American officials has been "ongoing" since last November, however, although the State Department didn't announce the problems until August.

Trump's team is maintaining diplomatic relations with Cuba and has avoided blaming the regime directly. "Cuba has told us it will continue to investigate these attacks and we will continue to cooperate with them in this effort," Tillerson said in a Friday statement.

That's not enough for Rubio.

"In light of these harmful attacks against American diplomatic personnel in Cuba, it is weak, unacceptable and outrageous for the U.S. State Department to allow Raul Castro to keep as many of his operatives in the U.S. as he wants," he said. "The Cuban government has failed its obligation under international treaties to keep foreign diplomats safe on its soil."

Another State Department official acknowledged Friday that Cuba bears responsibility for the safety of diplomats on the island. The official stressed that the Trump administration hasn't yet accused them of conducting the attacks and has not ruled out the possibility that a third-party country carried out the attacks on Cuban soil.

"The governments of the United States and Cuba have not yet identified the responsible party, but the government of Cuba is responsible for taking all appropriate steps to prevent attacks on our diplomatic personnel in Cuba," the senior State Department official said.