WASHINGTON — The United States removed Cuba on Thursday from its list of countries deemed to have insufficient security in their ports, eliminating a major impediment to free flow of ships in the Florida Straits.

Also Thursday, Cuba's government said it plans to do away with a penalty on converting U.S. dollars but warned the Obama administration not to expect more changes until the U.S. trade embargo is lifted.

Three days before President Barack Obama visits the island, Cuban Foreign Minister Bruno Rodriguez dismissed Obama's lofty rhetoric about using his visit to speak directly to the Cuban people about their future. In a stern and lengthy speech in Havana, he put Obama on notice that any attempt to circumvent the Cuban government by lobbying Cubans directly would not be warmly received.

Still, Rodriguez laid out a scenario under which the 10 percent penalty on dollars exchanged at banks and money-changers in Cuba would soon be lifted, making it easier and cheaper for Americans to spend time in Cuba.

Thursday's moves marked more steps toward normalized relations ahead of Obama's historic trip.

The U.S. action clears the way for cruise ships, cargo vessels and even ferries to travel back and forth with much less hassle. No longer will all ships have to wait to be boarded by the U.S. Coast Guard for inspections, though the Coast Guard still can conduct random inspections.

The Coast Guard, in an advisory on global port security, said Cuba now has effective security measures in its ports. That certification also removes the requirement that U.S. vessels maintain a higher level of security for access to ships while in Cuban ports.

Removing Cuba's designation under rules designed to fight terrorism also addresses a sore spot in the painful history between Cuba and the U.S., which dominated the island before relations were cut off amid the Cold War.

Obama has been easing restrictions on U.S. travel and commerce in Cuba since he and Cuban President Raul Castro moved to restore relations between the countries. Obama has quickened the pace in the days ahead of his trip to Havana, which starts Sunday.

Ahead of his trip, the Obama administration this week lifted the last meaningful restrictions on Americans visiting the island by allowing people to travel individually for loosely defined educational trips designed to increase interaction between Americans and Cubans. The U.S. also cleared the way for Cubans to earn salaries in the U.S. in most circumstances.

U.S. cruise lines are gearing up to start sailing to Cuba as Americans, long prevented from traveling to Cuba under the U.S. trade embargo, take advantage of the relaxed travel restrictions that Obama has put in place.

On Wednesday, a flight carrying mail to Cuba took off from the U.S. for the first time in a half-century, as part of a pilot program.