Group of Eight leaders meeting in Italy say they deplore the deadly post-election violence in Iran and they call the arrests of journalists unacceptable.
U.S. officials say the G8 leaders issued a strong and significant statement on Iran following a working dinner Wednesday night.
The officials say the leaders are losing patience with Iran's refusal to meet its international obligations to give up its suspected nuclear weapons program
The leaders did not threaten any new sanctions Wednesday. French President Nicloas Sarkozy said all eight agreed to give negotiations with Iran a chance until September, when another major summit convenes.
The G8 statement also demands Iran let foreign embassy employees work unhindered and it condemns Iranian President Mahmoud Ahmadinejad's denial of the Holocaust.
The G8 statement also condemns North Korea's nuclear weapons program and its missile tests. The leaders also gave their backing to Pakistan's fight against terrorism
U.S. officials at the summit also announced that President Obama will host a nuclear security summit next March. They said the president does not want to wait for an act of nuclear terrorism before such dangerous materials are secured, and black markets broken up.
Earlier Wednesday, G8 leaders announced a goal of deep cuts in greenhouse gas emissions, widely blamed for global warming.
On economic issues, the leaders affirmed their commitment to support financial growth and their opposition to trade barriers.
Other issues expected to come up at the summit include world hunger, aid to developing countries, the political crisis in Honduras, and ethnic violence in China's Xinjiang region.
The G-8 plan to meet with their counterparts from developing countries on Thursday.
Some information for this report was provided by AFP, AP and Reuters.