Protesting against the visit of Mahmoud Ahmadinejad in Brasilia. Photograph: Andre Penner/AP

Protests greeted Mahmoud Ahmadinejad in Brazil at the start of a South American tour intended to bolster the Iranian president's legitimacy and ease his country's international isolation.

Thousands of demonstrators took to the streets in Sao Paulo and Rio de Janeiro on the eve of Ahmadinejad's arrival to denounce his record on human rights, homosexuality and Israel.

The Brazilian president, Luiz Inácio Lula da Silva, was expected to welcome the visitor with red carpet pomp in the capital, Brasilia, before holding talks on economic and political co-operation. "It doesn't help isolating Iran," Lula said in his weekly radio address today.

Around 200 Iranian businessmen accompanied Ahmadinejad's delegation, in a sign of their eagerness to tap opportunities in a continent that does not consider Tehran a pariah. Iran's leader faces simmering discontent at home and hostility in the west, but in Latin America he has friends and allies among a leftist bloc led by Venezuela's Hugo Chávez and including Bolivia, Ecuador and Nicaragua.

"This is the first time in Latin American history that an Islamic government has been so present in the US backyard," Hamid Molana, an Ahmadinejad adviser, told the Irna state news agency. Luis Inácio Lula da Silva and Mahmoud Ahmadinejad in Brasilia. Photograph: Fernando Bizerra Jr/EPA

Achieving a first head of state invitation to Brazil was a diplomatic coup for Tehran because the region's heavyweight had previously kept its distance. Hobnobbing with Lula, one of the world's most popular leaders, shows that Ahmadinejad has diplomatic cards to play even if Europe, the US and much of the Middle East are against him.

"New orders should be established in the world," Ahmadinejad said before leaving Tehran. "Iran, Brazil and Venezuela in particular can have determining roles in designing and establishing these new orders."

Israel made a pre-emptive diplomatic strike last week when the president, Shimon Peres, visited Argentina and Brazil to lobby for a tough line on Iran's suspected quest for a nuclear bomb.

On Rio's Ipanema beach, groups representing gay people, artists, Christians, Jews, and Holocaust survivors carried protest banners and a giant cage containing white balloons as a symbol of Iran's "repressed values".

Opposition politicians criticised the visit. "One thing is a diplomatic relationship with dictatorships, another is to welcome their leaders in your home," Jose Serra, the Sao Paulo state governor, wrote in a newspaper article.

Ahmadinejad and Lula are expected to sign accords on biotechnology, energy and farming which, Tehran hopes, could boost bilateral trade from $2bn to $15bn. They may discuss co-operation on building nuclear plants. The Iranian president is due to address Brazil's congress and speak to university students before heading on to Bolivia and Venezuela.

The visit will test Brazil's ambition to be a serious diplomatic player by courting friendship with everyone. It has urged dialogue with Iran instead of cornering the regime with sanctions.

"If Brazil is somehow able to moderate Iran's policies on the nuclear question, or its practice in support of terrorist groups, it would give the Lula government a tremendous boost and enhanced global stature," said Michael Shifter, an analyst with the Inter-American Dialogue thinktank.

"But if Brazil doesn't succeed in influencing Iran's conduct, or is seen as indulging and legitimising such a questionable regime, then it risks alienating some in the US and Europe who expect Brazil to take a firm stand, and might even hurt its chances to get a seat on the UN security council."

Brazil has reportedly asked Ahmadinejad to steer clear of homophobic comments, Holocaust denial and threats against Israel. Another delicate point will be Tehran's crackdown on dissent after June's presidential election.

The US has welcomed Brazil's burgeoning diplomatic role but some members of Congress accused it of erring in "lending legitimacy" to Iran's leader.

Source: Guardian.co.uk