The Air Force is quietly shrinking its deployed force of land-based nuclear missiles as part of a holdover Obama administration plan to comply with an arms control treaty with Russia.

The reductions are nearing completion despite President Donald Trump's argument that the treaty gives Moscow an unfair advantage in nuclear firepower.

The reduction to 400 missiles from 450 is the first for the intercontinental ballistic missile, or ICBM, force in a decade — when the arsenal came down from 500 such weapons. The Air Force says the latest cut in Minuteman 3 missiles will be completed in April, leaving the deployed ICBM arsenal at its smallest size since the early 1960s.

In 2014, President Barack Obama's administration announced the planned ICBM reduction to tailor the overall nuclear force, including bombers and nuclear-armed submarines, to the New START accord that the U.S. and Russia sealed in 2010. Both nations must comply with the treaty's limits by February 2018.

The shrinking of the ICBM force runs counter, at least rhetorically, to Trump's belief that the U.S. has fallen behind Russia in nuclear muscle. In December, he tweeted that the U.S. must "greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes." He has criticized New START as a bad deal.

It's unclear how Trump intends to conduct a nuclear expansion, which critics call unnecessary and a potential drain on funds needed for non-nuclear forces. A long-term plan to replace and modernize the current nuclear force is already underway and will end up costing hundreds of billions of dollars.