(Adds Russian foreign ministry comments on Georgia)

BRUSSELS, June 3 (Reuters) - NATO Secretary-General Jaap de Hoop Scheffer said on Tuesday Russia should withdraw 400 troops deployed to repair railway lines in Georgia's breakaway region of Abkhazia.

"This deployment is clearly in contravention of Georgia's sovereignty and territorial integrity," he said in a statement, referring to Moscow's action which has provoked protests from Georgia.

"These forces should be withdrawn, and both Russia and Georgia should engage quickly in a high-level and open dialogue to de-escalate tensions," de Hoop Scheffer added of Russia's deployment of the unarmed soldiers there on Saturday.

Abkhazia, in the mountains above the Black Sea, is at the centre of a dispute between Moscow and Tbilisi over Georgia's intention to join NATO and Russian support for its rebel regions.

Russian soldiers patrol between Abkhazian and Georgian forces under a 1994 U.N. ceasefire which allowed Moscow to station up to 3,000 soldiers in the region. It reinforced its peacekeepers this year saying Georgia was preparing to invade -- an assertion Tbilisi denies.

"This deployment of Russian railroad forces does not appear to have any legal basis. It is not taking place in the context of the CIS peacekeeping mission, and it is against the express wishes of the Georgian government," de Hoop Scheffer said.

In Moscow, the Russian Foreign Ministry said in a statement issued before de Hoop Scheffer spoke that Georgia should stop saying Russia was bent on annexing Abkhazia.

"It would not be bad if the Georgian side would swap the senseless mantra about the threat of annexation and intervention for practical steps to strengthen ties," the ministry said.

For its part, the Kremlin said Russian President Dmitry Medvedev discussed Moscow's support for Abkhazia with Georgian President Mikheil Saakashvili by telephone on Tuesday.

EU foreign policy chief Javier Solana is due to travel to Tbilisi this week as part of a joint diplomatic effort with the United States aimed at defusing the tension. (Reporting by Mark John in Brussels and James Kilner in Moscow; editing by Jon Boyle)

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