Iran said Tuesday it is willing to negotiate with world powers on large-scale enrichment of uranium but will never give way on their key demand — to cease all enrichment, a process that can produce fuel for nuclear reactors or material for bombs.

The U.N. Security Council has demanded that Iran suspend all uranium enrichment activities and asked the U.N. nuclear watchdog agency to report back by April 28 on whether Iran had complied.

Foreign Minister Manouchehr Mottaki reiterated that Iran would not comply with the Security Council demand, saying the small-scale enrichment it resumed in February was strictly for research and was within its rights.

The United States and France have accused Iran of pursuing a secret program to build atomic weapons, but Tehran claims its nuclear program is peaceful and aimed only at generating electricity. Enrichment makes uranium suitable for reactor use but, taken to a high degree, it becomes suitable for a nuclear bomb.

"The enrichment of uranium ... is Iran's right as defined as a signatory to the Nuclear Non-Proliferation Treaty," Mottaki said. "One thing we can't give up and that is the right of the Iranian nation ... We can't hold a dialogue with any country about giving up our rights."

He added, however, that Iran was prepared to talk to the international community about large-scale enrichment.

Mottaki did not specify with whom Iran wants to hold negotiations. The United States is facing calls from its European allies for it to enter direct talks with Iran to resolve the standoff.

German Foreign Minister Frank-Walter Steinmeier underlined his country's support for U.S.-Iran nuclear talks ahead of a meeting in Washington with Secretary of State Condoleezza Rice.

"I think it is recognized here in Washington that the British and the German foreign ministers are positive on this question," he told reporters Tuesday.

State Department spokesman Adam Ereli said Monday the cause of the standoff was "not because the United States isn't in negotiations" but because Iran was defying international pressure and "moving with apparently great determination to develop an enrichment capability."

"So don't suggest that the way to solve this is for the U.S. to jump into negotiations. The way to resolve it is to get Iran to cease and desist from its active refusal to be a responsible member of the international community," Ereli said.

Iran and the United States have agreed to hold rare direct, high-level talks to discuss how to stabilize Iraq. While both sides have insisted the talks won't touch on the nuclear issue, U.S. officials say they suspect Tehran is looking to open the door for nuclear talks.

Since the U.N. Security Council issued its demand last week, Iran has taken a stance of rejection — while playing up hopes for a negotiated solution.

Mottaki said Iran's nuclear program had two options: cooperation or confrontation. "Iran prefers the first option," he said.

On Monday, hard-line Iranian President Mahmoud Ahmadinejad said the United States and Europe were "confused" if they thought they could stop Iran's nuclear ambitions. But he vowed Iran's nuclear program would be "transparent" and under the supervision of the International Atomic Energy Agency.

Past negotiations have faltered over the enrichment issue. Britain, France and Germany negotiated with Iran for two years on behalf of the European Union, endeavoring to persuade Tehran to abandon enrichment. Iran gave up on the negotiations last August and resumed parts of its nuclear program that it had suspended as a goodwill gesture.

Moscow then tried to persuade Tehran to accept a U.S.-backed compromise proposal under which large-scale uranium enrichment for Iran's nuclear program would take place in Russia. But negotiations ended in a stalemate after Tehran rejected a Russian demand to suspend uranium enrichment activities at home.