President Barack Obama's administration will announce further measures to ease travel and trade restrictions on Cuba on March 17, ahead of his historic visit to the Communist-ruled island this month, U.S. congressional sources said on Tuesday.

Details were still being worked out but the measures were likely to include changes to make it easier for individual Americans to visit Cuba if they qualify under 12 authorized categories of travel such as educational or cultural visits, as well as easing of trade and banking rules, said the sources, who were briefed on the matter by administration officials.

The White House said on Feb. 18 Obama would visit Havana March 21 and 22 in another step toward ending decades of animosity between the former Cold War foes. It will be the first visit to Cuba by a sitting U.S. president since 1928.

The White House has invited members of Congress to accompany the president, and congressional aides told Reuters about 20, mostly Obama's fellow Democrats, were expected to go. 

Obama's moves to normalize relations with Cuba have encountered stiff resistance from some lawmakers, mostly Republicans but also some Democrats, since the policy shift was first announced on Dec. 17, 2014.

They feel the White House is not getting enough back from Cuban President Raul Castro's government in exchange for the eased regulations. The administration believes that moves to loosen the embargo would help meet its goal of benefiting the Cuban people.

But even some Democratic aides said they were taken aback by news that there would be further moves by the White House without concessions from Havana. "Shouldn't we get something from the Cubans in return?" one asked.