President Obama declared "this is what change looks like" on Wednesday as he announced the U.S. and Cuba struck a deal to open embassies in each other's capitals, the latest step in re-establishing diplomatic relations with a country cut off from America for half a century.

"The progress we make today is another demonstration we don't have to be imprisoned by the past," Obama said in remarks from the White House Rose Garden, NBC News reported.

"When the United States shuttered our embassy in 1961, I don't think anyone thought it would be more than half a century before it reopened."

Obama sent a U.S. diplomat to deliver a note to Cuban President Raul Castro expressing a willingness to restore diplomatic ties, according to CNN. Castro also sent Obama a letter where he wrote: "We want to develop a friendship between our two nations that is based on the equality of rights and the people's free will."

The Cuban government said it is aiming to reopen its embassy on or after July 20, and White House deputy national security adviser Ben Rhodes told MSNBC the U.S. will open its embassy in Havana around the same time, according to NBC.

In December, following decades of Cold War hostilities and numerous attempted coups by the U.S., Obama announced that the U.S. was ending its "outdated approach" of isolating Cuba. In May, the country was removed from the U.S. list of state sponsors of terrorism.

It's an historic step that is certain to spark new battles in Congress. The executive branch has now done nearly all it has the power to do. For relations to be completely restored, lawmakers still need to confirm an ambassador, sign off on spending millions on the U.S. embassy and ease sanctions.

Perhaps the ultimate sign of rapprochement will be the removal of the crippling embargo against Cuba, which only Congress has the power to do.

Obama called for lawmakers to lift the embargo in January and again on Wednesday, saying, "Americans and Cubans alike are ready to move forward. I believe it's time for Congress to do the same. We've already seen members from both parties begin that work."

The Cuban Foreign Ministry said in a statement on Wednesday that until the embargo is removed, the U.S. and Cuba cannot have normal relations.

"There could be no normal relations between Cuba and the United States as long as the economic, commercial and financial blockade continues to be fully implemented, causing damage and scarcities to the Cuban people," the foreign ministry said in a statement received by CNN. "The blockade is the main obstacle to the development of our economy; it is a violation of International Law and affects the interests of all countries, including those of the United States."

The removal of the embargo could be complicated by a number of Republicans in ardent opposition. A few GOP presidential candidates were quick to criticize Obama for the normalization efforts.

"It's unacceptable and a slap in the face of a close ally that the United States will have an embassy in Havana before one in Jerusalem.," Texas Sen. Ted Cruz tweeted.

Florida Sen. Marco Rubio, a Cuban-American, vowed in a statement to oppose the confirmation of an ambassador to Cuba until the Cuban government makes a number of concessions, including "securing greater political freedoms for the Cuban people."

"The Cuban people today are not any freer politically or economically, and President Obama has failed to account for what the Castro regime has done in the last several years that warrants such an enormous shift in a longstanding U.S. policy," former Texas Gov. Rick Perry said, The Washington Post reported.