Nicolas Maduro was sworn in as Venezuela’s president on Friday at a ceremony attended by heads of states from Iran, Argentina and Cuba, among others, and amid protests from Venezuela’s opposition supporters.

Maduro, a former bus driver who rose to become the late Hugo Chavez’s protégé, narrowly won the presidential election on Sunday, beating opposition candidate Henrique Capriles.

Maduro, who represents the ruling United Socialist Party of Venezuela, or PSUV, won 50.8 percent of the vote, compared to Capriles' 49 percent — a difference of about 262,000 votes, out of 14.9 million ballots cast, according to Venezuela’s National Electoral Commission.

Capriles, the governor of Miranda state and the candidate for the umbrella opposition group Table for Democratic Unity, or MUD, said he did not recognize the results and demanded a recount.

In his first speech as president, Maduro offered a tribute to his predecessor Chavez who died on March 5 after a long fight against cancer.

“Every day I wake up thinking about him, and I go to bed thinking about him, in need of his guidance,” Maduro said, as reported by Reuters news agency.

Reaching out to the opposition supporters, Maduro said: “I call on those who for whatever reason did not vote for the candidate of the fatherland, I offer you an olive branch, I will work with you.”

During his speech, a man in a red jacket breached security and ran up to the podium. He pushed Maduro away and shouted into the microphone: “Nicolas, my name is Yendrick, please help me.” He was tackled and removed by security guards.

"Security has failed completely. They could have shot me up here," Maduro said upon resuming his speech.

Opposition supporters protested during the inauguration by banging on pots and pans, and playing salsa music, the BBC reported.

On Monday, clashes between police and opposition members in several provincial Venezuelan cities left seven people dead, with more than 60 injured and 139 arrested.

Russian President Vladimir Putin and Cuban leader Raul Castro congratulated Maduro on his win, according to the BBC.

The governments of Brazil, Peru, Ecuador, Colombia, Bolivia and Argentina, among others, have also voiced support for Maduro.

However, the U.S. State Department has backed Venezuelan opposition’s demand, saying it would not recognize Maduro without a recount. It was joined by the governments of Panama and Paraguay, the Associated Press news agency reported.

U.S. Secretary of State John Kerry said on Wednesday that Washington had not decided whether to recognize Maduro as president.

“That evaluation has to be made and I haven't made it,” Kerry told the House of Representatives Foreign Affairs Committee, as reported by Reuters news agency. “We think there ought to be a recount.”

“Obviously, if there are huge irregularities, we are going to have serious questions about the viability of that government,” he added.