When U.S. President Donald Trump and Russian President Vladimir Putin met in Helsinki in 2018, the pair alarmed allies with a friendly encounter where Trump sided with the Russian leader over his own intelligence agencies on election interference.

President Donald Trump's meeting with Russian leader Vladimir Putin is set for a military base in Alaska that was crucial to countering the Soviet Union during the height of Cold War and still plays a role today.

A top Putin aide said Ukraine will be the “central topic” of the Trump-Putin meeting, but trade and economic cooperation will also be on the agenda.