Colombian President Juan Manuel Santos said Thursday he welcomes international pressure to accelerate peace talks with the FARC guerrillas, which has mounted in recent weeks as fighting has intensified.

The international community has voiced alarm over Santos's decision in April to resume air strikes on the Revolutionary Armed Forces of Colombia (FARC), a move that prompted the rebels to scrap a unilateral ceasefire they had declared in December.

A new round of talks to warm relations between the European Union and Cuba has been scheduled for June 15 and 16 in Brussels, a Havana official told AFP Wednesday.

Cuba and the EU are in discussions to normalize their ties as the United States is similarly trying to restore relations and put an end to decades of enmity with the communist nation.

The White House signaled its intent Tuesday to veto legislation that would stymie President Barack Obama's push to open travel to Cuba, the latest political clash over his landmark foreign policy goal.

The transportation bill includes measures designed to scupper Obama's broader effort to thaw Cuba ties that were set in deep freeze during the Cold War.

President Barack Obama on Monday nominated Roberta Jacobson, a key figure in ongoing talks with Cuba, to be the next ambassador to Mexico.

Jacobson traveled to Havana in January, becoming the most senior ranking official to visit the communist island in 35 years.

Colombian soldiers killed two leftist rebels Saturday, the military said, amid renewed fighting that has shaken peace talks between the government and the FARC group.

The military said the latest clash occurred in the southwestern department of Narino, near the town of Tumaco.

The United States removed Cuba from its blacklist as a state sponsor of terrorism on Friday, in a landmark move aimed at paving the way towards normalizing ties frozen for half a century.

The decision means Cuba will now have better access to U.S. banking facilities and American aid, and a ban on arms exports and sales is also lifted.

As Cuba and the United States work on thawing ties, a group of U.S. lawmakers voiced optimism in Havana Wednesday that the U.S. economic embargo against Cuba could be lifted.

Led by Senator Tom Udall, the group of Democratic lawmakers was on a mission in an attempt to strengthen ties between the former Cold War foes following decades of enmity.

The United States and Cuba launched a fourth round of talks Thursday, seeking to overcome hurdles blocking the restoration of diplomatic ties, as Cuban exiles warned of a fresh crackdown on dissidents in Havana.

The delegations, led by top U.S. diplomat for Latin America Roberta Jacobson and Cuba's chief negotiator Josefina Vidal, met at the imposing State Department building in Washington, the hub of U.S. diplomacy.

Major differences remain between the United States and Cuba as they move to restore ties, especially on human rights, a top U.S. official said Wednesday on the eve of new talks.

"Significant differences remain between our two governments," top U.S. diplomat for Latin America Roberta Jacobson told U.S. lawmakers.

President Juan Manuel Santos on Tuesday said his defense minister was being reassigned and replaced, as the government wades through peace talks with leftist rebels.

The outgoing minister, Juan Carlos Pinzon, who has spent four years in the post, "will be taking over as ambassador in Washington," Santos said during an address.