Russia is trying to bolster its ties with friendly nations, as Western countries are stepping up military support for Ukraine.
The situation in eastern and southern regions is believed to be hanging in balance.
Russia's defense ministry said on Sunday that its troops are advancing in the southern Ukrainian region of Zaporizhzhia, but the Ukrainian military says it's pushing the invaders back in many locations.
Meanwhile, Russian Foreign Minister Sergey Lavrov is visiting South Africa. He is due to hold talks with International Relations and Cooperation Minister Naledi Pandor, who serves as the country's foreign minister.
Russia plans to hold a summit and an economic forum with African leaders in July in St. Petersburg.
Moscow is believed to be aiming to deepen relations with South Africa -- a member of the BRICS emerging economies and seen as friendly to Moscow.
Also, a delegation of Russian lawmakers led by lower house speaker Vyacheslav Volodin is visiting Iran. He is a close aide to President Vladimir Putin.
Iran's state-run media reported that Volodin will visit President Ebrahim Raisi after meeting the head of the Iranian parliament on Monday.
Russia has obtained drones from Iran to attack Ukraine's power infrastructure and other targets.