An all-out brawl erupted in front of the Cuban Embassy in Panama City on Wednesday, as a group of anti-Castro dissidents from Miami was confronted by a pro-Castro delegation from Cuba. Both groups are in town for the Summit of Americas, which Cuba is attending for the first time since 1962. It’s unclear what happened before the fight began. The Miami delegation of exiles claims that it was attacked while trying to march in a peaceful protest against the regime. Cuban state media called the exile “mercenaries,” who had “links to terrorist groups.” Representatives of the official Cuban delegation temporarily abandoned the summit in response to various protests, saying that “For reasons of dignity we can not be asked to share the same roof with these mercenaries.”

U.S. Rep. Ileana Ros-Lehtinen (R-Fla.) and other staunch anti-Castro politicians blamed Cubans for the scuffle and demanded increased protection from Panamanian Police. She called the incident an attack by “Cuban regime thugs” on U.S.-based dissidents engaged in a “peaceful” pro-democracy protest. Some American lawmakers are uneasy with concessions being made by the White House in recent weeks as the U.S. warms relations with Cuba. On the same day as the attack, Senator Robert Menendez (D-NY) criticized the anticipated removal of Cuba from America’s state sponsors of terror list. Congresswoman Ros-Lehtinen echoed his comments, saying that the brawl was evidence of Cuba’s “disregard for human rights.”

“As President Obama arrives in Panama this week, he must not look the other way as Americans are feeling the violent wrath of Castro and Havana’s disregard for human rights,” she said. “This violent act today should be another wake up call to the Obama administration that its misguided policies are only emboldening the Castro regime to continue its oppressive tactics unabated.”

“Assassins! Mercenaries!” the pro-castro crowd yelled as the two side engaged in fisticuffs in a park and on the street, in video captured by La Estrella de Panama. It’s unclear how the altercation started, but video recordings of the incident clearly show both sides engaging in violent confrontation. At one point in the encounter, Miami dissident Orlando Gutierrez Boronat, 50, spars with an unidentified middle-aged man holding a suit jacket over his shoulder. Both men appear to be able to walk away, but proceed to throw punches. A few uniformed men, ostensibly Panamanian police officers, are also seen in the video. They unsuccessfully try to restrain the crowd, which included dozens of pro and anti-Castro demonstrators. The dissident delegation eventually retreats into two vans while being attacked by the Castro supporters.

It’s a rocky start for the Seventh Summit of the Americas, where warming U.S.-Cuban relations were expected to take center state and unite leaders across Latin America and the Caribbean.  concerns over human right violations in Cuba and economic sanctions imposed by the U.S. continue to divided the 35 national delegations of the Western Hemisphere.