HAVANA, June 12 (Xinhua) -- The Cuba-U.S. relations "are at a low point, but they can get worse" due to the "sinister plans" by Washington policy-makers, a Cuban official said here on Wednesday.

"Those responsible for the policy towards Cuba at the White House seek to abruptly end diplomatic ties," said Johana Tablada, deputy director of U.S. affairs at Cuba's Foreign Ministry, at the University of Havana's international conference on U.S. studies.

Tablada warned of serious setbacks in bilateral relations brought by the adoption of U.S. "extreme measures" against Cuba, which will affect the island country economically and politically.

The United States announced last week that it has banned cruise ships and group people-to-people educational travel to Cuba, a new move signaling its worsening ties with the Caribbean island.

"The U.S. government hasn't been able yet to find a sufficiently credible lie to continue imposing its policy against Cuba," said Tablada.

However, Washington could inflict further damage or completely end diplomatic relations, going against the interests of most U.S. people and businesses.

"We are immune to threats and pressures, although we are concerned about the suffering that might be caused upon our people with the application of these extreme measures," she said.

U.S.-Cuba ties have deteriorated under the administration of U.S. President Donald Trump, which has rolled back the detente initiated by his predecessor Barack Obama.

In the last two years, official contacts and cooperation mechanisms between the two governments have been reduced to a minimum, she said.