President Donald Trump has reiterated his call for the United States to be "top of the pack" when it comes to nuclear weapons.

His latest comments echo a tweet sent following his November election win in which he pledged to increase US firepower.

Speaking to journalists at the White House, Trump said he would like to see a world with no nuclear weapons, but is concerned that the US has fallen behind on nuclear weapon capacity.

Critics say the US and Russia already have more than enough warheads to deter any nuclear attack.

What is behind the president's latest thinking and could it provoke a new arms race?

Presenter: Hazem Sika

Guests:

Barry Pavel - former National Security Council adviser to President Barack Obama and President George Bush

Pavel Felgenhauer - Russian security and defence analyst

Christian Ruge - arms control expert