Brussels - Iran's authorities should allow peaceful demonstrations and engage with the West on disarmament and relations with Afghanistan, Sweden's foreign minister said Monday, 10 days before taking over the European Union's rotating presidency.

"They should respect the right that is there in the Iranian constitution for peaceful demonstrations ... The use of lethal violence against peaceful demonstrators is never tolerated in any country whatsoever," Carl Bildt told reporters in Brussels.

Sweden is set to take over the EU presidency on July 1, and will be tasked with steering the bloc's common foreign policy until the end of the year.

Bildt was speaking after an EU summit on Friday said that the 27-member bloc "firmly condemns (Iran's) use of violence against protesters, resulting in the loss of lives."

Bildt said that the killing of further demonstrators over the weekend "makes it necessary to be even stronger in our message."

And he called on the Iranian regime to answer demonstrators' concerns over the transparency of the country's disputed presidential election, saying that "it's up to them to establish the credibility of their political process."

But he also stressed that the West wants to work constructively with Iran on the question of its nuclear programme and on relations with Afghanistan.

"Irrespective of the outcome of this particular (political) process ... we have an interest in engaging with Iran," he said.

While he admitted that he was "concerned" by the result of events in Iran, he insisted that "The need to reach out to Iran and the hope that they will answer our efforts positively is still there."

Bildt may get that answer as early as Thursday, when he is set to join the foreign ministers of the Group of Eight (G8) world powers in Trieste, Italy, to debate developments in Afghanistan and Pakistan. Iran has also been invited to send a top official to the meeting.

Bildt is one of the EU's heaviest diplomatic hitters, having served as Sweden's prime minister from 1991 to 1994. (dpa)