MOSCOW (AP) — President Vladimir Putin is visiting an Arctic archipelago as part of Russia's efforts to reaffirm its foothold in the region.

Putin toured the Franz Josef Land archipelago, a cluster of 192 islands where the Russian military has recently built a new runway and worked to open a permanent base.

During Wednesday's trip, Putin inspected a cavity in a glacier that scientists use to study permafrost. He also spoke with environmental experts who have worked to clean the area of Soviet-era debris.

Prime Minister Dmitry Medvedev and other senior officials accompanied him.

The Kremlin has named reaffirming the Russian presence in the Arctic as a top priority amid an intensifying rivalry over the region that is believed to hold up to one-quarter of the planet's undiscovered oil and gas.