President Donald Trump says his administration has already had “very serious” discussions with Russia about its war in Ukraine and that he and Russian President Vladimir Putin could soon take “significant” action toward ending the grinding conflict.

For those with a vested interest in Ukraine, U.S. President Donald Trump's first week in office was a bit of a rollercoaster. During his first presidential term, Trump famously praised Russian President Vladimir Putin.

President Trump jabs at the Russian leader with threats; Vladimir Putin responds with flattery. But there are notable signals in their jousting, including a revived discussion about nuclear arms control.