President Vladimir Putin (search) said Monday he won't seek a third term in 2008, but vowed not to allow "destabilization" in Russia following the vote, leaving the door open for drastic action in the event of a crisis.

In an interview with Dutch media on the eve of a visit to the Netherlands, Putin reiterated that he opposes changing the constitution to prolong his time in power — a possibility that has been widely discussed because of his popularity and control over parliament.

But Putin said that the 2008 presidential election will be a "serious, difficult test for Russia" and stressed that full power and responsibility for the fate of the country will remain in his hands until the new president is sworn in.

"I will not allow any destabilization in Russia, in the interests of the ... peoples of the Russian Federation," Putin said in the interview with Dutch broadcaster Netwerk and financial newspaper NRC Handelsblad.

He did not elaborate, but the statement raised the possibility that Putin could take unpredictable measures in the name of stability in the event of unrest or a political crisis in the weeks between the election and the new president's inauguration.

He suggested such actions probably would not be necessary, saying that he believes "the political forces in Russia are mature enough to understand their responsibility to the people," and said the election would be a fair one in which the candidate with the most votes will win.

"At the same time, I want to draw your attention to the fact that according to the constitution, authority is handed over to the new president after he takes the oath of office, and until then the current president holds full responsibility for the situation in the country," he said.

Russia's experience with power transfers purely by election is limited: Putin was made acting president by Boris Yeltsin (search) before he was first elected in 2000, and Yeltsin became president when Russia was still part of the Soviet Union.

With the Kremlin seeking increasingly tight control over politics and society and nervously eyeing other ex-Soviet republics where longtime leaders have been ousted recently, tension is palpable more than two years before the March 2008 election.

Putin has repeatedly said he opposes changing the constitution to remain in power — without strictly ruling it out — and has also hinted vaguely of a continuing role for himself and said he will try to groom a successor.

"Of course, I am not indifferent about whose hands the country that I have dedicated my whole life to ends up in," Putin said. "But if every new head of state who comes to power changes the constitution as he sees fit, soon there will be nothing left of this state."

Asked if Russia could ever join the NATO (search) or the European Union (search), Putin did not rule out eventual membership in the military alliance said Moscow would consider joining the EU if invited — but would not come knocking at the door.

"Since childhood I have been taught never ask for anything and never to regret anything," he said.

He emphasized that, for now, the important thing was to implement decisions aimed at bringing Russia and the EU closer.

Putin also stressed the importance of enabling visa-free travel between Russia and EU countries, something he has pushed hard for in dealings with the European Union.

"Let's really make Europe a continent without borders," he said. "Why do we talk all the time of human rights in general terms? Let's give people the opportunity to at least visit each other freely."

Putin also defended the treatment of oil tycoon Mikhail Khodorkovsky (search), who is serving an eight-year prison sentence in Siberia after a tax evasion and fraud trial widely seen as Kremlin-backed punishment for a politically powerful rival. Lawful punishment for a crime was a sign "not of destabilization, but on the contrary, of stability and the strength of the state," Putin said.

In an interview that touched heavily on Russia's violence-plagued Caucasus Mountain region, Putin said Chechnya (search) and the surrounding area must remain part of Russia.

Terrorists must be treated mercilessly, he said, criticizing what he called a European "tradition of appeasing any aggressors, any extremists."

"I believe that this is a very dangerous tendency ... One cannot pay off terrorists even with handouts, even by giving them asylum," he said.