Britain is also to take over the leadership of the NATO Very High Readiness Joint Task (VJTF) from next year with 3,000 troops in the UK and Germany on standby to move with as little as five days' notice.
The move comes amid continuing concerns among the Western alliance regarding the intentions of President Vladimir Putin following Russia's annexation of Crimea from Ukraine in 2014.
Mr Cameron, US President Barack Obama, German Chancellor Angela Merkel, and French President Francois Hollande are meeting with other leaders from the alliance and world bodies in the Polish capital. Through this,NATO will attempt to show a united front just weeks after Britain, one of its senior members, voted to leave the EU.
At the two-day meeting, Russia will be on the agenda. Mr Cameron is expected to say that “Nato isn’t seeking a confrontation with Russia but that Russia does need to understand that Nato is united and will defend any ally, and that the approach to Russia must be guided by the principles of defence and dialogue”.
This move has come after a terrifying report, published by the Canadian Security Intelligence Service (CSIS), that Russia is 'mobilising for war' and could demolish the states within 60 hours if it could. It also stated that, “The CSIS report, entitled 2018 Security Outlook, states: “Russia is not modernising its military primarily to extend its capacity to pursue hybrid warfare.
“It is modernising conventional military capability on a large scale; the state is mobilising for war."