The Russian lower house of Parliament, the Duma, on Wednesday ratified a new START nuclear treaty with the US. 

The United States and Russia had "agreed in principle" to extend the arms treaty by five years following a phone call between US President Joe Biden and Russian President Vladimir Putin Tuesday.

A Kremlin description of the call between the two leaders said they had both "expressed satisfaction" that diplomatic notes had been exchanged earlier Tuesday confirming that the treaty would be extended,

The extension doesn't require approval from lawmakers in the US. 

Deadline approaching 

The White House press secretary Jen Psaki said the two leaders agreed to have their teams "work urgently" to iron out the details of the extension before the treaty's expiration date, February 5. 

The New START (Strategic Arms Reduction Treaty), was signed in 2010 by former US President Barack Obama and his Russian counterpart at the time, Dmitry Medvedev.

The treaty limits each party to 700 deployed intercontinental ballistic missiles (ICBMs) or deployed submarine-launched ballistic missiles (SLBMs), 1,550 nuclear warheads on deployed ICBMs and SLBMs, and 800 deployed and non-deployed ICBM launchers. 

It also envisions a rigorous inspection regime to verify compliance. 

The last nuclear arms control agreement 

Biden had indicated during his presidential campaign that he favored extending the treaty, and Russia has long proposed its extension without any conditions or changes. 

However, negotiations to extend the treaty were stalled by the administration of former US President Donald Trump, which insisted on tougher inspections for Russia and for China to be included, which Beijing refused. 

During Trump's term, the US withdrew from a separate nuclear weapons control agreement with Russia, the Intermediate-Range Nuclear Forces (INF) treaty, making New START the last  remaining nuclear weapons control treaty between Russia and the US.