Russia is preparing to obtain three Soviet-era strategic bombers from Ukraine this week, the first of 11 planes left behind after the Soviet collapse that now are being traded by Ukraine for forgiveness of part of its natural gas debts to Moscow.

Russian air force commander Anatoly Kornukov was quoted by the Interfax news agency today as saying the two Tu-95 Bear bombers and one Tu-160 Blackjack are to be flown in the next two or three days to Russia's bomber base at Engels, 520 miles southeast of Moscow.

The flight marks the end of eight years of negotiations between Russia and Ukraine over the planes. Russia currently has only six of the Tu-160s and is to bring eight more from Ukraine, more than doubling its fleet. However, neither the condition of the planes in Russia nor the ones coming from Ukraine is known. Some are believed to be in need of major repairs.

Russia now has 57 of the slow-flying, propeller-driven Bear bombers and is to get three more, built in 1991, from Ukraine. In addition, Russia is to get 500 AS-15 Kent cruise missiles that also were left behind in Ukraine.

The deal--often delayed because of disagreements over the value of the planes--was set at $285 million and will be deducted from Ukraine's debt to Russia for natural gas, which exceeds $1 billion. Russia is expected to fly all 11 planes to Engels by the end of the year, officials said.

Aviation has always been the smallest leg in Russia's land-sea-air triad of nuclear forces, and the additional planes will bolster its long-range forces. However, the additional planes can carry only a limited number of nuclear warheads compared to those stationed on submarines and on land.

For example, if fully operational, the three Tu-95 bombers can carry 16 missiles each, and the eight Tu-160s can carry 12 each, for a total additional capacity of 144 warheads. Russia's current strategic nuclear arsenal is about 5,620 warheads, but it is shrinking because of arms control agreements as well as obsolescence.

However, the bombers and missiles may also carry conventional warheads and some of the Ukrainian planes may be also useful for spare parts. Russia also has some unfinished Tu-160s at the factory where they were manufactured in the Tatarstan region.

Russian newspapers said some criticized the deal as an unnecessary trade designed to help President Leonid Kuchma of Ukraine win reelection. Not all the bombers left in Ukraine are being brought back to Russia, however; dozens that are considered unfit to fly and in need of major repairs are being left there.