Ukraine has reported some success in pushing back Russian forces in the eastern region of Donetsk, but says the situation remains tense.

Russia is on the offensive in the east and south. Ukrainian authorities on Monday said two residents were killed in a missile attack in the southern region of Zaporizhzhia. They said Russian shelling also killed one person in the eastern Kharkiv region.

Ukraine's deputy defense minister Hanna Maliar posted on social media Monday that Ukrainian troops were pushing back and fortifying their positions near Urozhaine in the eastern region of Donetsk.

But she acknowledged that the situation remains tense and difficult, citing Russian attempts to make advances near the regional capital of Donetsk.

In Russia, an army forum opened in the suburbs of Moscow on Monday with representatives from about 70 countries reportedly taking part. Russian media say China, India and African countries are among the participants.

China says Defense Minister Li Shangfu will deliver a speech and hold talks with Russian officials.

President Vladimir Putin delivered a video address at the forum's opening ceremony. He stressed that Russia has exported many advanced weapons to its partners.

Russian defense minister Sergei Shoigu said, "The much-touted Western equipment actually proved to be far from flawless." He suggested that Russian weapons were far superior, even though many of them have been destroyed in Ukraine.