A US national being held in Russia on espionage charges will appear in court Tuesday for a bail hearing, but his lawyer told journalists he expects his client to remain in custody.

Russian President Vladimir Putin on Wednesday voiced support for Venezuelan leader Nicolas Maduro as he visited Moscow seeking financial assistance for the socialist country's collapsing economy.

The Security Council will hold an emergency meeting on Monday after Russia confirmed it had seized three Ukrainian naval ships by force in a strait near Moscow-annexed Crimea, U.S. ambassador to the U.N. Nikki Haley said.

Moscow is intensifying efforts to wean its economy off the dollar as Washington considers tough new sanctions that could deny Russia access to foreign debt markets and cut its banks from the greenback.

President Vladimir Putin has repeatedly slammed the U.S. unit's dominance on the world's stage but the country's previous efforts to de-dollarize its economy have so far had little success.

The Kremlin said Wednesday it was ready to discuss the possibility of a summit in Washington next year between Russian President Vladimir Putin and US counterpart Donald Trump.

The Kremlin on Monday said the world would be less safe if Washington goes ahead with plans to withdraw from a Cold War-era nuclear weapons treaty that banned intermediate-range missiles. 

"Such steps, if taken, will make the world more dangerous," said presidential spokesman Dmitry Peskov as he rejected claims by US President Donald Trump that Russia had violated the 1987 Intermediate-Range Nuclear Forces Treaty (INF).

Uzbekistan and Russia signed business deals worth more than $27 billion on Friday as Russian President Vladimir Putin paid his first state visit to the former Soviet republic since long-ruling leader Islam Karimov died in 2016.

Russian opposition leader Alexei Navalny was released from jail Sunday after three weeks behind bars for organizing anti-Kremlin protests, his second spell in detention in as many months.

Russia's Vladimir Putin on Monday spoke to Syria's Bashar al-Assad for the first time since last week's downing of a Russian military plane, telling him of Moscow's plan to deliver a new S-300 air defense system to the Syrian army.

The deal to avoid a Syrian government offensive on Idlib province is still being worked out by Russia and Turkey, the UN said Thursday, stressing that the threat to civilians remained high.