Russia's military backing for the Syrian regime only risks sending more extremists to the war-torn country and could further hamper any effort at bringing peace.
The White House said it was open to limited talks with Moscow following the controversial deployment of Russian troops and heavy weapons to war-torn Syria.
Russia wants talks with the US military to ensure their forces do not come into conflict as it continues its build-up in Syria, Secretary of State John Kerry said.
Ukrainian President Petro Poroshenko expanded a list of sanctions against Russian companies and individuals held responsible for the ex-Soviet state's eastern uprising and for Moscow's annexation of Crimea.
Russian President Vladimir Putin is "open to dialogue" and to meeting with his US counterpart Barak Obama when he visits the UN headquarters later this month.
As Russians voted in local elections set to confirm the ruling party's dominance, the opposition reported mass vote rigging and police stormed the office of independent vote monitors.
Billionaire mogul and White House frontrunner Donald Trump accused US President Barack Obama of paying "lip service" on Ukraine and failing to stand up to Russian strongman Vladimir Putin.
Ukrainian President Petro Poroshenko accused Russia of challenging the "entire democratic world" by annexing Crimea and allegedly arming separatist rebels in the east of his ex-Soviet state.
Ukrainian Prime Minister Arseniy Yatsenyuk criticised as "anti-Ukrainian and anti-European" a deal between Russia's energy giant Gazprom and several Western firms to build a second gas pipeline under the Baltic Sea.
Karaganda native Olga Veldyaksova has successfully passed the first stage of the Russian Voice singing contest, Russian version of world renowned The Voice.
Ukrainian Prime Minister Arseniy Yatsenyuk warned that any attempt to hold "unlawful" elections in rebel-run areas in the country's east would constitute a breach of a February peace deal.
The United States has asked Greece to ban Russian supply flights to Syria from its airspace, amid growing US fears that Moscow is increasing its military backing for Syrian President Bashar al-Assad.
These are mere economics laws: we have to keep prices equal to those of Russia as we have no customs barriers and the movement of goods across the border is free: President Nazarbayev.