The German leader and the US vice president disagree over the best approach to Iran, with Merkel favouring negotiations.

German Chancellor Angela Merkel has defended the nuclear deal with Iran that severely limits its ability to produce enriched uranium in the face of strong opposition from the United States.

While there is an agreement with the US on the aim of putting Iran under pressure over its nuclear programme, there is a difference of opinion on the means, the chancellor told the Munich Security Conference on Saturday.

The deal needed to be preserved to prevent Iran from building nuclear weapons, and this “small anchor” should be used to pressure Iran in other areas, Merkel said.

The US has withdrawn from the deal hammered out in 2015 by the five permanent members of the United Nations Security Council plus Germany. France, the United Kingdom and Germany aim to rescue the deal.

Speaking at a Middle East conference in Warsaw on Thursday, US Vice President Mike Pence called on the three countries to withdraw from the deal.

The US charges Iran with meddling in conflicts throughout the region and Pence accused it of anti-Semitism akin to the Nazis at the conference on Friday.

“We have the regime in Tehran that’s breathing out murderous threats, with the same vile anti-Semitic hatred that animated the Nazis in Europe,” Pence told reporters on Air Force Two before landing in Munich.

He said that visiting Auschwitz in Poland after attending the conference in Warsaw had made him reflect to “strengthen the resolve of the free world to oppose that kind of vile hatred and to confront authoritarian threats of our time”.

The three-day Munich conference began on Friday. Around 30 heads of states and governments are attending to discuss transatlantic relations, tensions between Russia and the West and Middle Eastern conflicts.

Reporting from Munich, Al Jazeera’s Jamal Elshayyal said “there are so many conflicts as well as challenges to security for so many countries” and “each country perceives different threats and sees different solutions”.

While the US and Germany have both spoken, the forum has yet to hear from Russia, China and Iran.

“Whether there’s going to be common ground … we’ll have to wait and see,” Elshayyal said.