The United States crossed 45 companies and individuals off a Cuba sanctions blacklist on Tuesday - most of which were defunct companies, sunken ships or deceased people with links to Cuba.

The Treasury's Office of Foreign Assets Control (OFAC) removed six people, 28 companies and 11 vessels from the list during an ongoing review of older cases.

Most operators purged from the list were based in Panama. The ships had either sunk or were not in service.

Four people who were just taken off were deceased. Among them was Amado Padron, a Cuban executed by firing squad in 1989.

The US Treasury Department said the delisting was aimed at clearing "out-of-date" names from its list of Specially Designated Nationals (SDN). Those on this list are banned from trading with US individuals or companies and face hefty fines if caught doing business.

"While these removals are not related to the recent changes to our Cuba sanctions program and rather reflect OFAC's consistent effort to review and update its SDN list, these delistings are in line with the President's Cuba policy," OFAC said.

Lifting the entire trade and financial embargo on Cuba requires the approval of Congress - an uphill battle since both houses are currently under Republican control.

'A decade-long stealthy quest'

The development is the latest in the recent thawing of tensions between the former Cold War rivals. Washington and Havana agreed to restore diplomatic relations in December after more than 50 years of hostility - an event widely seen as the culmination following 18 months of secret diplomacy.

But a recent investigation by Reuters news agency uncovered that US President Barack Obama had embarked on this process a decade ago, when he first expressed interest in the country.

The White House quietly proposed back-channel talks with Cuba in April 2013, after getting wind that Havana would be receptive. But negotiations dragged on throughout the years, as both sides couldn't agree on the exchange of prisoners.

The talks moved forward last spring, when Obama enlisted the help of the Vatican to appease staunch critics, like Cuban-American Senator Robert Menendez. Pope Francis raised the Cuba issue with the US President in March 2014 and then wrote personal letters to both Obama and Cuban President Raul Castro.

The deal was finalized in late October in Rome, ahead of the historic Dec. 17 announcement.

Last week Washington and Havana wrapped up their third round of talks on reestablishing formal relations. Obama is eager to reopen embassies ahead of the Summit of the Americas in Panama on April 10-11, but the two sides still disagree on several issues, including compensation for American property nationalized after the Cuban Revolution and freedom of movement for diplomats.

The two sides are next due to meet in late March, when they will address the issue of human rights for the first time.

EU also seeking to normalize ties

The European Union is also keen to improve bilateral relations with Cuba. Both sides agreed to speed up talks, hoping to reach a deal by the end of the year, said EU foreign policy chief Federica Mogherini on Tuesday.

She also signed an agreement to give 50 million euros ($55 million) to modernize Cuba's agricultural sector.

After the 28-member bloc removed diplomatic sanctions in 2008, Europe has become Cuba's top trade partner after Venezuela, with trade being at $3.6 billion (3.3 billion euros) in 2013. It is also a major investor in Cuba's key tourism sector.

Mogherini reiterated EU opposition to the US trade embargo against Cuba, saying there wasn't any competition between the US and the EU with regard to ties to the Caribbean island as they were "different processes."

Russian Foreign Minister Sergei Lavrov also called for an end to the US embargo during his tour of Latin America this week. According to media website Cubadebate, Lavrov said Russia would work with Cuba to help end US trade sanctions.

He added Russian companies were interested in investing in the country's development.

el/hg (AP, AFP, dpa, Reuters)