The plan is to build a nuclear power research center and light water reactor, with a heat generation capacity of 10 megawatts, the atomic agency said in a statement. The reactor will use 20 percent enriched nuclear fuel, it said.

"So far, a political decision has been taken that says yes, we can do this," agency spokesman Sergei Novikov said by telephone. "This agreement simply opens the door so a contract can be concluded."

Agency officials would now carry out negotiations with their counterparts in Myanmar to hammer out details of the deal, he said.

The announcement came as U.S. Secretary of State Condoleezza Rice was in Moscow in a bid to ease rising tensions. Myanmar, formerly known as Burma, has been under U.S. and international sanctions since 1990, when the military junta refused to accept the election victory of opposition leader Aung San Suu Kyi.

               
Suu Kyi has been held under house arrest for long periods, and governments and activists alike have rallied to her cause to highlight human rights abuses in the country.

The deal threatened to add to U.S. criticism of Russia, which is already helping Iran build a $2 billion nuclear reactor at Bushehr.

Kremlin spokesman Dmitry Peskov brushed aside potential criticism. "No one is arguing about the right of every state to have peaceful nuclear energy," he said. "We can only welcome achievements in this sector of industry, which is very developed and very safe from the point of view of nonproliferation."

The atomic agency statement said the nuclear project in Myanmar, which is a signatory to the Nuclear Nonproliferation Treaty, would come under International Atomic Energy Agency control.

An IAEA official who requested anonymity said the organization had "not been informed by Myanmar about the construction of any nuclear facility." Were it to be built, it would be "subject to IAEA safeguards inspections," the official said.

Construction of the reactor will be handled by state-owned Atomstroiexport, which is controlled by the atomic agency, the statement said.

"It's too early to talk about anything concrete, from timeline to location to expenses," Atomstroiexport spokeswoman Irina Yesipova said. "There's a huge number of factors to consider."

Yet the deal is a long time coming. The project was first floated in 2000 and talks were nearly concluded before Russia pulled out in 2003, Novikov said.

Myanmar's reluctance to pay cash up front has been cited as the reason for that deal falling apart. Today, flush with petrodollars, Russia can afford to be more patient. "Their advantage is their stuff is cheap and they'll do business with anybody," said Alexander Kliment, an analyst at Eurasia Group, referring to the Federal Atomic Energy Agency.

"The commercial benefits of a deal with a country as small as Myanmar are not immediately evident," he said.

A research reactor, which tends to be smaller inside, could be used to train local staff or test new technology, analysts said. And Myanmar, which suffers from partial power outages because of lack of investment, could use nuclear power to meet a large part of its energy needs.

David Steinberg, an expert on Myanmar and the director of Georgetown University's Asia Studies program, said the deal was likely prompted by Myanmar's desire to balance Chinese influence in the country. "Burma has been entirely dependent on China for military goods," he said from Washington. "This nuclear deal fits into the pattern of balance [of Chinese influence]," he said.

Steinberg said he did not believe Myanmar would seek to sell the technology to a third party. Myanmar and North Korea restored diplomatic relations last month after nearly 15 years. "There is the fear in the U.S. that if you have a military junta like Burma ... they're going to go and sell the stuff on. They may be brutal, but they're not stupid," he said.

The nuclear deal comes as energy ties between the two countries are growing. Two Russian oil companies based in Kalmykia recently signed a production sharing agreement with Myanmar to explore for oil and gas in the country's northwestern Sagaing region. Last week, the two companies, Silver Wave Sputnik Petroleum and Silver Wave Energy, began drilling their first test well.