The two sides agreed last September that Russia would supply the Czech Republic with 26 combat helicopters as part payment of its outstanding debt to the country.

The 16 Mi-171 transport helicopters and 10 Mi-35 combat helicopters worth a total 184 million dollars (142 million euros) are due to be delivered by the end of 2006.

Czech Defence Ministry official Mira Trebicka said Tuesday that the Russians had still not ratified the relevant contract.

She said the Czech Republic should receive the first three Mi-35s and three Mi-171s in the first half of this year.

Outdated Antonov and Tupolev type planes are still used to transport Czech soldiers and equipment but they will be banned from flying abroad in about two years because they exceed noise limits.

The Czech Republic will have to adapt the modernised helicopters from Russia to NATO standards. They have to be equipped, for example, with a device distinguishing friendly planes from enemy aircraft, and with NATO communication systems.

The additional costs are estimated at 1.2 billion koruna.

Inherited from the days of the Soviet Union, the Russian debt to the Czech Republic is part civil and part military. The former is managed by the finance ministry, the latter by the defence ministry.

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