UK Prime Minister David Cameron speaks to Iran's president on eve of nuclear negotiations

British Prime Minister David Cameron has contacted Iranian President Hassan Rouhani ahead of negotiations over Tehran's nuclear program in what Downing Street says was the first such conversation between the leaders of the two countries in more than a decade.

Britain, the U.S. and four other world powers are to resume talks with Iran in Geneva on Wednesday.

Cameron's office said the two leaders agreed during their telephone conversation Tuesday that significant progress had been made in recent Geneva negotiations over the nuclear issue and that it is important to "seize the opportunity" in the next round of talks.

Cameron also stressed Iran's need to comprehensively address the international community's concerns about Tehran's nuclear program, his office said.