By Jim Muir BBC correspondent in Tehran

Chris Patten, the European Union's commissioner for external relations, is in Iran for a three-day visit to initiate more talks aimed at producing a trade and cooperation agreement with the Islamic republic.

The negotiations are to begin on Wednesday and Mr Patten will meanwhile be holding talks with Iranian leaders on the political bones of contention the two sides are trying to resolve.

We have different viewpoints... but we would like to try to understand one another better Chris Patten

Mr Patten has been in Tehran before, but this is the first time he has come on his own as the EU's foreign affairs chief.

Speaking after a first round of talks with Iranian Foreign Minister Kamal Kharazi, Mr Patten made it clear that his visit reflects the importance the EU attaches to relations with Iran.

His trip comes just a few days after President Bush, in his State of the Union address, said the Iranian government was oppressing its own people, pursuing weapons of mass destruction and supporting terrorism.

While the Americans continue to cold-shoulder Tehran, Mr Patten left no doubt that the Europeans are going down a different road, one of constructive engagement, involving dialogue on the concerns raised by Washington.

'Understanding'

"We have concerns about a number of issues, including the manufacture and proliferation of weapons of mass destruction around the world," Mr Patten said.

"We have different viewpoints on human rights [and] the Middle East... but we would like to try to understand one another better.

Bush accused Iran of oppressing its people

"I hope that we can actually have a better relationship and work together as responsible members of the international community to deal with problems which are common to all of us, including terrorism."

The trade and cooperation negotiations started in Brussels in December and Mr Patten will be kicking off the second round here in Tehran on Wednesday.

They are linked to a separate dialogue on human rights and other political issues.

The EU is insistent that the linkage is there and that economic relations won't be able to go far without progress on the other issues.

The negotiations are expected to go on sporadically for many months before reaching a conclusion.