Under the deal, Iran agreed to a continued moratorium on its quest to complete development of a full nuclear fuel cycle, the precursor to building an atomic weapon.
"What this does is ensure that Iran continues with its suspension of processing of nuclear materials," British Foreign Secretary Jack Straw told a team of reporters after the meeting.
The deal is considered a success for the EU team which has urged Iran to completely shut down its nuclear processing facilities or face referral to the U.N. Security Council. Wednesday's agreement delayed such a referral.
Under the agreement, reached by a high-level delegation including Tehran's top nuclear negotiator Hassan Rohani and the foreign ministers of Germany, France and Britain, the European nations agreed to provide Tehran with a detailed proposal focused on how the EU would uphold its end of a bargain to reach a final deal.
"We believe we could reach a final agreement within a reasonably short time," Rohani said, but added Iran's government still must sign off on this latest deal.
The Iranian government has denied accusations from the EU and the United States that its nuclear program, kept secret for almost two decades, is a front for a military weapons initiative. The government claims any research and development of nuclear technology is solely for generating electricity. Iran also has asserted its right as a signatory to the nuclear Non-Proliferation Treaty to produce nuclear energy for civilian purposes.
The treaty, signed in 1965, bars countries other than the five recognized nuclear powers -- the United States, Britain, France, China and Russia -- from developing nuclear weapons.
"We will remain committed to all our promises and at the same time we want all the rights applicable to countries members of the Non-Proliferation Treaty," Rohani said, according to Reuters.
Rohani's comments were echoed in Tehran by a group of 200 students who staged a protest outside the British Embassy in support of their country's nuclear program, the Associated Press reported.
The Bush administration, which has threatened economic sanctions if Iran refuses to stand down, said Wednesday it remained unconvinced of Tehran's intentions.
"Iran hid its nuclear activity from the international community for two decades. That is why we are skeptical about their activities," White House spokesman Scott McClellan said.
Wednesday's talks were considered a last-ditch effort on the part of the EU to prevent Iran from restarting its nuclear program. New negotiations scheduled for July will take place after Iran's presidential elections on June 17, the AP reported.