Moscow, Feb 27 (IANS/ITAR -TASS): Marines of Russia's Baltic and Northern Fleets were Thursday boarding large landing ships as part of a military exercise of ground and air forces on the very doorstep of neighbouring Ukraine, where a tumultuous struggle last weekend drove the president from power and pushed Russia and the West into a face-off reminiscent of the Cold War.

Groups of the Pskov airborne troops were also moving to an airfield to board aircraft to be ready to land at planned areas, Russia's defence ministry press service told ITAR-TASS.

The landing grounds would be known to the troops only after the aircraft took off and were headed for the areas, the press service added.

All the mobile units of paratroops and marines are ready to land anywhere under any climate conditions, it said.

Meanwhile, tank units and troops of the western military district were being carried by rail, a defence ministry source said.

General staff officers had handed over envelopes with information to commanders to bring troops to certain railway sites and airfields to transport them to military training grounds located far from the deployment bases.

The commanders would know where the troops would be brought and what tasks they would carry out after they opened the envelopes, the source said.

On Feb 26, Russian President Vladimir Putin had ordered the defence ministry to conduct an urgent complex drill to test the combat readiness of forces of the western and central military districts. The military exercise is scheduled to last till March 3.

Senior defence and government officials have said the exercise was not related to the events in Ukraine -- which were being watched with growing alarm -- but they also said there was no reason to postpone them either, and the geopolitical message was clear.