Russia should not prevent former Soviet republics from fully integrating with the West, US Defense Secretary Robert Gates said Wednesday, adding that they posed no threat to Moscow.

Gates made the remark after talks with Estonian Prime Minister Andrus Ansip centered on Russia's invasion of Georgia in August and also a massive cyberattack a year ago on this tiny Baltic state during a bitter dispute with Moscow.

"Russia has no need to impede a sovereign country's desire to more fully integrate with the West," Gates told reporters. "Doing so is not a threat to Russia's security, nor is greater cooperation on cyber issues."

He announced that Washington will sponsor an Estonian center of excellence on cyber defenses, lauding the government for sharing its growing expertise in the field.

Gates also was to meet with Baltic defense ministers and join NATO defense ministers Thursday in an informal meeting with Ukraine to discuss Kiev's aspirations to join the alliance, a sore point with Russia.

"NATO's doors are open and will stay open," NATO Secretary General Jaap de Hoop Scheffer reaffirmed after arriving in Tallinn.

Western relations with Moscow hit a post-Cold War low in August when Russia stepped in on the side of the Georgian breakaway region of South Ossetia and invaded Georgia, another former Soviet republic with NATO aspirations.

Tensions have remained high, fueled by Moscow's resentment of NATO's expansion into the former communist bloc and its anger over US plans to install missile defenses in central Europe.

Earlier Wednesday, Moscow rejected US proposals aimed at easing its concerns over missile defense, saying they were "nothing new."

"We won't agree to these proposals and will negotiate with the new administration," a Kremlin official quoted by Russian news agencies said.

The State Department was still working to set up a new round of missile defense talks with Moscow in mid-December, a US defense official said.

"We still very much wish to partner with Russia to combat the growing ballistic missile threat emanating from Iran, as evidenced by Tehran conducting another missile test this week," said Geoff Morrell, the Pentagon press secretary.

"Though the Iranians failed yet again, they are clearly determined to develop a weapon capable of reaching Europe and for that matter Russia so it continues to be in our mutual interest to work together on this issue."

Russian President Dmitry Medvedev threatened a day after the US elections last week to deploy missiles in Russia's Baltic Sea territory of Kaliningrad to "neutralize" the planned US missile defense system, which has NATO-wide backing.

"I think these remarks made by the Russian president were unhelpful and unnecessary," Scheffer said.

Ex-communist NATO members Lithuania and Poland, which border Kaliningrad, have been adamant that the alliance needs to undertake additional steps to ensure it can meet its "Article Five" commitment to defend all its members against attack.

Estonia's Ansip expressed confidence that NATO would abide by the commitments. But, speaking through an interpreter, he said that "circumstances have changed, NATO defense plans need to change accordingly."

Gates said: "I would simply add that we engage in prudent planning, we are always reviewing our assessment of the security situation."

He said the US European Command had sent representatives to Estonia in September "so these consultations and talks continue."

It was unclear how much weight Gates' views would have at the Tallinn meeting. Although he represents the waning influence of the outgoing US administration, Obama's advisers have not ruled out his staying on.

The latest Russian moves appeared aimed at widening divisions within NATO while at the same time testing the reaction of president-elect Barack Obama's incoming administration.

EU foreign ministers on Monday agreed to resume talks with Moscow on a strategic pact, which had been frozen since the invasion of Georgia.

"We are not looking to punish the Russians, but it has caused us to re-evaluate the relationship," a senior US defense official said, speaking on condition of anonymity.