WASHINGTON - US President Barack Obama on Friday sought to cement his administration's rapprochement with Cuba, unveiling a new round of loosened trade rules, including lifting limits on rum and cigar imports.

In a statement, Obama said a new policy directive laid out an official framework for continuing normalization of relations with the island nation that was aimed at making this "irreversible."

"This new directive consolidates and builds upon the changes we've already made, promotes transparency by being clear about our policy and intentions, and encourages further engagement between our countries and our people," Obama said. The move makes normalization federal policy even though Congress has not lifted the fifty-year-old US trade embargo on Cuba, according to senior administration officials who spoke to reporters in a conference call.

The two countries announced the start of normalization in 2014.

The changes could be reversed when a new administration takes office, they said, speaking on grounds of anonymity, but presidential directives generally remain in effect until further notice.

Treasury Secretary Jacob Lew said in a statement that the changes sought to break down economic barriers, allowing more personal contact among Cubans and Americans and growth in the private sector.

"These steps have the potential to accelerate constructive change and unlock greater economic opportunity for Cubans and Americans," Lew said.

The US Treasury and Commerce Departments on Friday announced regulatory changes due to take effect on Monday which would allow joint medical research and funding, civil aviation and safety services and payments for travel by foreign nationals to and from Cuba.

Foreign vessels will no longer be prohibited from loading or unloading cargo in US ports for 180 days after calling on a Cuban port. And air cargo will now also be allowed to transit Cuba in addition to cargo carried by sea.

Authorized US travelers will now also be permitted to import more Cuban liquor and tobacco in their luggage for personal use.

The Treasury Department will also permit the sale of services to build and repair Cuban infrastructure.

"More commercial activity between the US and Cuba benefits our people and our economies," Commerce Secretary Penny Pritzker said in a statement.