The Vostok 2018 military exercise in eastern Russia was already billed as Russia’s largest war game since 1981. China’s Defense Ministry announced on Thursday it will send 3,200 troops from the People’s Liberation Army to join over 100,000 Russians in exercises from September 11 to 15.

The Chinese troops will bring at least 900 tanks and 30 aircraft with them. If Russia’s boast of the biggest exercise since the Cold War is accurate, over 1,500 Russian tanks and 120 aircraft will be involved.

A small force from Mongolia has also been invited to participate, mirroring the way Russia’s huge Cold War exercises included partners from Warsaw Pact countries. Most of the actual former members of the Warsaw Pact will be eyeing Vostok 2018 with some trepidation. This week marked the 50th anniversary of the Pact’s invasion of Czechoslovakia.

“Despite furious Western attempts to isolate the Kremlin, countries still want to collaborate with Russia. By arms sales and cooperation, Russia is using its military strength to increase its geopolitical presence in the world,” Russian Defense Minister Sergei Shoigu declared.

While Russia flexes its military muscles, China is eager to give the new and improved People’s Liberation Army a field test.

The South China Morning Post on Thursday quoted Beijing-based military observer Zhou Chenming, who pointed out that while China has invested heavily in modernizing its military, it has a pronounced shortage of troops with actual combat experience. Russia has also invested heavily in military modernization over the past few years.

Zhou said China is also eager to shore up its alliance with Russia and put on a more menacing display than either Moscow or Beijing could manage on their own:

“China also wants to show its support for Russian President Vladimir Putin, who is facing various diplomatic challenges, especially criticism from the US Secretary of State [Mike Pompeo] over Moscow’s annexation of Crimea,” Zhou said. He said the site chosen for the war games was deliberate. “Putin wants to use the Russian military’s war games with the PLA to show its military muscle, but he doesn’t want to irritate the United States too much and raise the possibility of a misjudgment by the Trump administration, so he chose the less sensitive Trans-Baikal region in the Far East, far from US allies in Europe,” Zhou said.

Another analyst, Song Zhongping of Hong Kong, said China would send its most elite troops to Vostok 2018 for battlefield combat training to supplement the counter-terrorism and anti-piracy drills they have received. Song suggested that China and Russia are both looking to send a carefully calibrated message of impressive, but not quite provocative, strength to Washington.

CNN noted the dates for the Vostok exercise overlap with the Eastern Economic Forum in Vladivostok, an event hosted by Russian President Vladimir Putin which Chinese President Xi Jinping is expected to attend.