MOSCOW (AP) — Russian President Vladimir Putin on Friday ordered the country’s military to increase the number of troops by nearly 170,000 to a total of 1.32 million, as Moscow’s military action in Ukraine continues into its 22nd month.

Putin’s decree was released by the Kremlin on Friday and took force immediately. It brings the overall number of Russian military personnel to about 2.2 million, including 1.32 million troops.

It is the second such expansion of the army since 2018. The previous boost by 137,000 troops, ordered by Putin in August 2022, put the military’s numbers at about 2 million personnel and about 1.15 million troops.

The Defense Ministry said the order doesn’t imply any “significant expansion of conscription,” saying in a statement that the increase would happen gradually by recruiting more volunteers. The ministry cited what it called “the special military operation” in Ukraine and the expansion of NATO as the reasons for beefing up the army.

NATO’s “joint armed forces are being built up near Russia’s borders and additional air defense systems and strike weapons are being deployed. The potential of NATO’s tactical nuclear forces is being increased,” the statement read.

Boosting Russian troops is an appropriate response to “the aggressive activities of the NATO bloc,” the ministry said.

Last December, Russian Defense Minister Sergei Shoigu declared that the country needed a force of 1.5 million “to guarantee the fulfillment of tasks to ensure Russia’s security.” He didn’t say when the military would reach that size.

The Kremlin previously considered the size of its military as sufficient, but the calculus changed after hopes for a quick victory over its neighbor were shattered by fierce Ukrainian resistance.

Amid the continued hostilities, Russia and Ukraine both have kept a tight lid of secrecy on their military casualties. The Russian military has confirmed only just over 6,000 military casualties, but the West had much higher estimates. In October, the U.K. Defense Ministry tweeted in a regular update that Russia has “likely suffered 150,000-190,000 permanent casualties,” a number that included troops that have been killed and permanently wounded.

The Russian authorities have undertaken various efforts to give a boost to the army.

In August 2022, Putin ordered an increase in the size of the Russian military to 1.15 million starting from Jan. 1, 2023. The following month, he ordered the mobilization of 300,000 reservists to beef up his forces in Ukraine. That number is counted as part of the military’s current strength.

While Putin said there was no need to round up more, his mobilization decree is open-ended, allowing the military to call up additional reservists when needed. That decree also banned volunteer soldiers from ending their contracts.

Regional authorities have tried to help beef up the ranks by forming volunteer battalions for deployment to Ukraine. All across Russia’s vast territory, a campaign to entice more men to enlist has been underway for months, with advertisements promise cash bonuses, recruiters making cold calls to eligible men and enlistment offices working with universities and social service agencies to lure students and the unemployed.

The deputy chair of Russia’s Security Council, Dmitry Medvedev, said Friday that more than 452,000 men have enlisted into the army as contract soldiers this year.

Some media reports and rights groups say that the Russian authorities also offer amnesty to prisoners in exchange for a tour of military duty.

These efforts come on top of the regular draft, which calls up around 120,000-140,000 men twice a year for a one-year tour of compulsory service. The authorities insist that those conscripted for mandatory service aren’t being deployed to Ukraine.

All Russian men from age 18 to 27 must serve one year in the military, but a large share avoid the draft for health reasons or deferments granted to university students. The share of men who avoid the draft is particularly big in Moscow and other major cities. This year, the authorities raised the upper age limit for mandatory service to 30 starting from Jan. 1.

The Russian military rounds up draftees twice a year, starting April 1 and Oct. 1. Putin ordered the drafting of 130,000 conscripts during the fall earlier earlier this year, and 147,000 in the spring.