A day after his inauguration as Uruguay's first left-wing president, Tabare Vazquez has bolstered links with leftist leaders in the region.
Vazquez welcomed "the Cuban people once again at this house"
Mr Vazquez signed a deal for energy co-operation with his Venezuelan counterpart, Hugo Chavez.
He completed agreements on human rights with Argentine leader Nestor Kirchner and held talks with the Brazilian President, Luis Inacio Lula da Silva.
Uruguay is the fifth Latin American nation to move to the left recently.
Venezuela, Chile, Brazil and Argentina also have left-wing governments.
The BBC's Elliott Gotkine in Buenos Aires says Mr Vazquez appears to be making good on his promise to put regional integration at the top of his foreign policy.
Meeting the left
President Vazquez restored full diplomatic relations with Cuba immediately after being sworn in.
Uruguay broke off diplomatic ties with Cuba three years ago under outgoing President Jorge Battle.
Cuban leader Fidel Castro accused him of being a traitor for supporting US efforts to condemn Cuba's human rights record in a United Nations vote.
President Vazquez said that ties should never have been broken off and he welcomed "the Cuban people once again at this house".
Vazquez's election brought to an end almost 180 years of two-party rule
The Venezuelan leader and Mr Vazquez agreed to exchange Uruguayan food for Venezuelan fuel, and to work together on a state-run regional TV channel.
Mr Vazquez asked Mr Kirchner to help to look for the bodies of a reported 150 Uruguayans who disappeared on Argentine soil in the 1970s and 1980s, when both countries were under military rule.
After holding talks with President Lula, the new leader and his Brazilian counterpart inaugurated a Brazilian-owned brewery in the north of Uruguay.
Correspondents say that despite his warm meeting with President Chavez, Mr Vazquez's economic policy will be closer to the cautious centre-left approach of President Lula.
Focus on poverty
Mr Vazquez's victory in presidential elections last October ended almost 180 years of two-party rule.
The 65-year-old's win at the head of the Frente Amplio (Broad Front) coalition party ended the long dominance of the ruling Colorado Party, whose candidate came third, and the National Party, who came second.
Thousands of Vazquez supporters celebrated in the streets of the capital, Montevideo, as he took office.
Our correspondent says the country's shift to the left is down to disillusionment with the right and the failure of its economic policies.
The left has also rejected many policies which had scared off voters in the past, he says.
Mr Vazquez, a former mayor of Montevideo, signed a $100m anti-poverty programme as one of his first acts in office.
"We have pledged changes and we will bring in changes," he said.