Azerbaijan has bought oil and natural gas from Russia to meet internal demand while exporting its own energy riches to the West. Russia also has been the main market for Azerbaijan’s fruit and vegetable exports. It also is a key transport corridor for Russia’s trade with Iran and other partners in the Middle East.

The rift, provoked by the deaths of two ethnic Azerbaijanis in Russian custody, was the latest in a series of spats that revealed a deeper diplomatic rift between the former allies.

Officials say police in Azerbaijan's capital of Baku searched the offices of Russia’s state-funded news outlet Sputnik amid rising tensions between the two countries after the deaths of two ethnic Azerbaijanis during a police raid last week in a Russian city.