The companies announced that Alibaba will contribute its AliExpress Russia e-commerce website to the joint venture. Russian mobile operator Megafon will swap a 10-percent stake in Mail.ru for a 24-percent stake in AliExpress Russia.

The partnership will be backed by Russia's sovereign-wealth fund, the Russian Direct Investment Fund (RDIF), which will acquire a 13-percent stake in AliExpress.

Alibaba Group President Michael Evans called the joint venture "an exciting step in Alibaba's international expansion."

"By partnering with Russia's leading consumer internet platform, AliExpress Russia will help digitize and transform the retail value chain in Russia, enabling a seamless and innovative experience for consumers as well as creating significant opportunities for Russian entrepreneurs and SMEs (small and medium-sized enterprises) to grow in their home market and expand globally," Evans said when announcing the deal.