Iran's new hardline President, Mahmoud Ahmadinejad, will not change the country's nuclear policy, says Tehran's foreign ministry spokesman.
Mahmoud Ahmadinejad will differ little from Iran's supreme leader
Hamid Reza Asefi said talks on the issue would continue with Europe, who he urged to show patience until Mr Ahmadinejad announced his programme.
Mr Ahmadinejad has said Iran's nuclear negotiators have been frightened in the talks - and this should change.
Israel has become the latest country to express concern over his election.
Deputy Prime Minister Shimon Peres called it "a contest between extremists".
Israel views Iran as its biggest threat, says the BBC's Matthew Price in Jerusalem.
Iran disputes the Jewish state's right to exist and when Israel lobbies foreign governments, it is Iran's nuclear programme which tops the agenda rather than other issues closer to home, our correspondent says.
"The nuclear issue is a part of a macro policy, and our position will not change with the change of a president," the Iranian foreign ministry spokesman said.
"With this election, the Islamic republic of Iran is more capable of confronting challenges, and the Europeans have to take this into consideration," Mr Asefi said.
Iran insists it wants to produce nuclear power to generate electricity and Mr Asefi said: "We will not give up our right."
"We will reach bright results through negotiations," he said.
It is common knowledge in Iran that nuclear policy is decided ultimately by the country's Supreme Leader, Ayatollah Khamenei, and it is very unlikely Mr Ahmadinejad would differ from the leader, anyway, says the BBC's Frances Harrison in Tehran.
The result of the elections means conservatives are now in control of every elected and unelected institution of government in Iran.
The White House responded to the poll result by expressing support for "those who call for greater freedom for the Iranian people".
The state department said Iran was "out of step... with the currents of freedom and liberty that have been so apparent in Iraq, Afghanistan and Lebanon".
UK Foreign Secretary Jack Straw said there were "serious deficiencies" in the election, noting that many reformists, and all women candidates, had been barred from standing.
He urged the new president to deal with international concerns over Iran's nuclear programme.
The European Union said it was ready to work with "any Iranian government" willing to progress on the questions of human rights, nuclear energy and other matters of concern.
Mr Ahmadinejad, 49, won 62% of the vote in Friday's presidential run-off poll.
He will be Iran's first non-cleric president for 24 years when he takes office in August.