The foreign minister of Argentina, caught in the middle of a scandal in which he and his government are accused of brokering an illegal deal to cover up Iran’s alleged role in a deadly terrorist attack, said this week in a rare interview that the charges were “ridiculous.”

Moreover, Argentine Foreign Minister Héctor Timerman said, he has no knowledge of what happened to the prosecutor found shot to death the night before he was to present allegations of the secret deal to lawmakers. And the foreign minister expressed deep reservations about the possibility of U.S. assistance in determining how prosecutor Alberto Nisman died — despite calls by some Argentine and U.S. legislators for the FBI to help investigate and an offer of help from the U.S. government.

“There are some problems in the United States that the FBI cannot solve,” Timerman told The Washington Post in a telephone interview from Buenos Aires. “I don’t know why they think the FBI can solve problems all over the world.”

Timerman made his comments during one of his first lengthy interviews on the topic amid the controversy that has plunged Argentina into turmoil. A State Department official said the U.S. government had offered to assist Argentine authorities in their investigation of the prosecutor’s death, though Timerman said he was not aware of the offer.

Nisman was killed with a bullet to the forehead hours before he planned to lay out his findings alleging that Timerman, acting on behalf of President Cristina Fernández de Kirchner, had agreed to absolve Iran of involvement in the 1994 bombing of a Buenos Aires Jewish community center that killed 85 people. In exchange, Nisman was to allege, Argentina would sell grain to Iran and Iran would sell oil to Argentina as part of a broadening commercial relationship between the two countries.

Ever since Nisman’s body was found on Jan. 18, Argentina has been seized by speculation. Did Nisman commit suicide or was he murdered and, if so, by whom?

Last week, Argentine officials confirmed that draft criminal indictments for both Fernández and Timerman had been found in the trash at Nisman’s apartment after his death.

Speaking with The Post on Monday, Timerman, a Jew whose father was a crusading journalist jailed by the regime governing Argentina in the 1970s, spoke in personal terms to reject the core of Nisman’s allegations. He said he would not have sought any deal to cover up Iran’s role in the bombing of the center, which remains a Jewish landmark in the country.

“I will not throw out of the window my history, the history of my family, the history of my government, the history of my friends who were killed during the dictatorship. I will not do that,” he said. “For what? To get what? Oil?”

Nisman, who had led the investigation into the bombing since 2004, had concluded that Iran masterminded the attack in cooperation with the Lebanese-based Hezbollah militia.

In 2007, at Nisman’s urging, the international police agency Interpol issued “red notices,” international arrest warrants, for Iranian suspects.

Before his death, Nisman was preparing to allege that Fernández and Timerman had secretly agreed to seek the withdrawal of the red notices as part of a publicly announced 2013 deal with Iran to establish a joint judicial panel between Argentina and Iran to interview suspects.

Timerman vigorously disputed the claim, saying he opposes the idea personally and philosophically and had no legal authority to make such a request. He noted that the head of Interpol has publicly rejected the claim and said no Argentine official sought the withdrawal of the arrest warrants. The 2013 deal, Timerman said, was intended to provide a way to move the case forward given that Iranian law prohibits extradition and Argentine law does not allow for suspects to be tried in absentia.

“That is why we decided it might be a possibility, maybe, to convince the Iranians, the government of Iran to allow the judge to go to Tehran to investigate suspects,” he said.

He said the goal was to find a legal process to allow the case to proceed.

“We are not going to put a bomb under the car of an Iranian,” he said — a veiled reference to the 2008 car bombing that killed Imad Mughniyah, the Hezbollah leader who was one of those Nisman had sought to charge in the Jewish center bombing. The Post recently reported that he was killed in a joint operation between Israel’s Mossad and the CIA.

“The only thing in which Argentinians believe is in the judicial system,” Timerman said.

Fernández, a colorful and controversial president, at first said she believed Nisman had committed suicide. Later, she said he had been murdered by elements of the Argentine intelligence community in an effort to discredit her government.

Timerman declined to repeat those allegations. He said neither he nor Fernández stood to gain from the death, which prevented Nisman from appearing before Argentina’s National Congress, where tough questions might have been lodged about his claims.

“Who gained by having Mr. Nisman dead?” he asked. “Not me. Not the president.”

Rosalind Helderman is a political enterprise and investigations reporter for the Washington Post.