Iran could radicalize with UN sanctions-Brazil

* Sanctions would hit poor people, could trigger revolt

* Difficult for Iran to show it has no bomb capability

* Brazil neither for nor against Iran

By Fernando Exman

BRASILIA, April 6 (Reuters) - United Nations sanctions against Iran over its nuclear program could make the Islamic Republic more radical and cause its population to revolt, Brazil's foreign minister said on Tuesday.

Brazil has urged continued dialogue with Iran even as Western powers push for a new round of sanctions in the U.N. Security Council over a program they believe is aimed at developing nuclear bombs.

"A regime like Iran's, with sanctions, will tend to radicalize, dig in its heels, joining opposition and government in a position of intransigence," Foreign Minister Celso Amorim told Brazil's Senate foreign relations committee.

"The result of growing sanctions is that the country will become more isolated. Sanctions always hit the poorest people ... that will cause the population to revolt," Amorim said.

He denied that Brazil backed Iran, even though President Luiz Inacio Lula da Silva welcomed his Iranian counterpart Mahmoud Ahmadinejad to Brazil last year and plans to visit Tehran in May.

"It's not a question of Brazil being for or against Iran. Brazil is in favor of peace and negotiated solutions," Amorim said. "Brazil wants to have relations (with Iran) like it does with other big countries."

Iran should cooperate with international inspectors, Amorim said. But the country could do little to prove it did not have nuclear arms capability.

"It's hard to prove a negative."

Latin America's largest country has a revolving seat on the U.N. Security Council.

Lula has said that he wanted the International Atomic Energy Agency to be more proactive in reviving stalled talks with Iran. He will attend a nuclear security summit in Washington next week.

(Reporting by Fernando Exman; Writing by Raymond Colitt, editing by Alan Elsner)