Vladimir Putin has threatened to employ his nuclear capabilities seven months after the start of the invasion of Ukraine. 

The Russian leader is also calling on military reservists as they seek to further their advance on the neighbouring country. 

In a speech delivered via a Russian television station, he said he's not "bluffing" when he says he'd be ready to use nuclear weapons to defend Russia.

Michael Williamson, a leader at the London International Christian Church, has been working to set up churches in Ukraine during the war. 

Speaking to Premier Christian News after Putin's threats were made, he said: "I believe God is a sovereign God and, although it's a very dangerous and disheartening thing to hear from Putin, when you go throughout the Bible, you'll find that God allowed his people to get to a point of desperation, where he was troubling the nations.

"I'm reminded of Asa. The Bible says one nation was being crushed by another nation because God was troubling them, But Asa found strength by turning to the Lord and praying, and knowing that if there is a power greater than nuclear - it's God's power. 

"Sometimes in human history, God has to put his people in a position where there's nowhere else we can look but to him. We can't live up to a greater nuclear power, because the only the enemy of war is war itself, from my perspective. 

"I think it's time for God's people to call upon their God who is greater than suffering greater than sadness, greater than fear; to really turn to him on their knees and pray for us to put down our political beliefs, our racial beliefs, our denominational beliefs, and really come together as a family and really pray to our God, and I earnestly believe that when we turn to God, God will hear us from from here, and God can stop a nuclear assault and can stop Putin"