Russian President Vladimir Putin on Friday compared the U.S. proposal to build a missile defense shield in Eastern Europe to the Cuban missile crisis of the 1960s.

"Analogous actions by the Soviet Union, when it deployed missiles in Cuba, prompted the 'Caribbean crisis,"' Putin said at a news conference at the end of a European Union-Russian summit in Portugal, using the Russian term for the Cuban missile crisis.

"Such a threat is being set up on our borders," he said.

At the same time, Putin suggested the tension was much lower that during the 1962 Cuban missile crisis because Russian-U.S. relations have moved on since the Cold War. He also said he believes the United States is listening to Moscow's concerns about its missile plans.

Putin said his relationship with President Bush helps solve problems in relations with the U.S., calling him a friend.

State Department spokesman Sean McCormack disputed the comparison of the missile crisis with the missile defense system, saying "I don't think they are historically analogous in any way, shape or form."

McCormack said there were "clear historical differences between our plans to deploy a defensive missile system designed to protect against the launch of missiles from rogue states, such as Iran, and the offensive nuclear test capability of the missiles that were being installed in Cuba back in the 1960s."

White House press secretary Dana Perino noted that Putin also said he believes that there's a path where the United States and Russia can work to find a way to get a missile system that works for both countries.

"I think if anyone takes a look at his entire comments and looks at them objectively, there's no way you could walk away without thinking that he thinks that we can work together," she said, adding that Bush is convinced that Putin shares the belief that Iran should not be allowed to have a nuclear weapon.

The U.S. plan would install a radar base in the Czech Republic and 10 interceptor missiles in Poland — both former Soviet satellites that are now NATO members. It is part of a wider missile shield involving defenses in California and Alaska which the United States says are to defend against any long-range missile attack from countries such as North Korea or Iran.

Russia strongly opposes the idea, saying Iran is decades away from developing missile technology that could threaten Europe or North America, and it says the U.S. bases will undermine Russia's own missile deterrent force.

Turning to his future, Putin said he would not assume presidential powers if he became prime minister after finishing his term in the spring.

"If someone thinks that I intend to move, let's say, into the government of the Russian Federation and transfer the fundamental powers there, that's not the case," he said at a news conference. "There will be no infringement on the powers of the president of the Russian Federation, at least while it depends on me."

The popular Putin is barred from seeking a third consecutive term in the March 2008 presidential election. But he suggested earlier this month that he could become prime minister after his term ends in May, leading some to speculate that the substantial powers now invested in the presidency might be transferred to the prime minister.

After repeating his insistence that he does not intend to change the constitution in order to run for a third term, Putin said he had not yet decided where and in what capacity he would work as former president. He is expected to remain an influential figure in Russia.

Putin will lead the ticket of the dominant United Russia party in December parliamentary elections. An overwhelming victory for the party could turn the legislature into a new power base for Putin and give him a claim to continued authority based on his popularity.

Putin and EU leaders put a positive spin on Friday's Portugal summit. Many observers had approached the meeting with low expectations, given deepening disputes between Moscow and the 27-nation union over issues such as energy, human rights and the Balkans.

Putin, European Commission President Jose Manuel Barroso and other EU officials repeatedly characterized the talks as "open, frank and productive."

However, the two sides failed to sign a new cooperation agreement to replace an expiring one, and two minor deals — on drug trafficking and steel exports — were the only concrete results announced.

Topping the list of concerns for a growing number of European nations is Russian energy policy — the reliability of supplies and the intentions of state-run oil and gas companies. Russia already provides 30 percent of EU energy imports, including 44 percent of natural gas imports.

The state-controlled gas giant OAO Gazprom has recently moved to acquire assets in Europe and strike bilateral deals with some EU countries.

That has led the EU to consider new restrictions on non-EU companies owning majority stakes in gas pipelines or electricity power grids without additional agreements — much to the Russians' consternation.

Earlier, Putin tried to assure European leaders that Russian investment was not to be feared.

"When we hear in some countries phrases like, 'The Russians are coming with their scary money,' it sounds a bit funny," he said.

He said money flowing into Russian government coffers — largely from oil and gas exports — was being used to resolve domestic problems. And he noted that private foreign investors hold large amounts of shares in Gazprom.

Putin held talks Friday with Barroso and Portuguese Prime Minister Jose Socrates, whose country holds the EU's rotating presidency, at an 18th-century baroque palace in Mafra, a small town about 30 miles north of Lisbon.