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.

Authorities in Azerbaijan arrested two journalists from the local branch of a Russian state news agency on Monday in a move likely to further stoke tensions with Moscow following arrests in Russia of ethnic Azerbaijanis suspected of serious crimes.

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.