The Vostok-2018 war games in eastern Siberia last month marked Russia's biggest military exercise in more than 30 years, with about 300,000 Russian, Chinese and Mongolian troops taking part.
More than just an exercise, the war games were a public relations opportunity to showcase military hardware, Russia's second-biggest source of income after oil.
During Vostok-2018, Russia showed off the S-400 surface-to-air missile, one of the country's most advanced and marketable weapons systems in recent years.
The S-400 is a massive upgrade to the S-300, its predecessor which was recently sent to Syria.
Because of its capabilities, several countries including China, Saudi Arabia, Turkey, India and Qatar have said they are willing to buy the S-400.
Almost every government that announced it was planning to buy the system was threatened with some kind of diplomatic retaliation from the US, NATO or adversaries.
The reason for this blowback, according to several experts Al Jazeera interviewed, is not only because the S-400 is technologically advanced, it also poses a potential risk for long-standing alliances.
"The S-400 is among the most advanced air defence systems available, on par with the best the West has to offer," said Siemon Wezeman, senior researcher with Stockholm International Peace Research Institute's (SIPRI) arms transfers and military expenditure programme.
"Its radars and other sensors, as well as its missiles, cover an extensive area - the radar has a range of at least 600km for surveillance, and its missiles have ranges of up to 400km," Wezeman told Al Jazeera.
"It's precise and it manages to track a very large number of potential targets, including stealth targets."
Other advantages are its modular setup and high mobility, meaning it can be set up, fired and moved within minutes.
"It's intended to be a one-size-fits-all missile system. It can be configured with long-range, semi long-range, medium-range and even short-range weapons systems, depending on how the individual user wishes to configure the S-400," Kevin Brand, military analyst working with the Council on Foreign Relations, told Al Jazeera.
"It's very rugged, it's adaptable and it's a road-mobile system, something many countries are seeking to evolve to."
Turkey, a NATO member, is one of the most significant potential buyers of the S-400.
Speaking at a graduation ceremony for military officers, Turkey's President Recep Tayyip Erdogan said in August that Ankara would try to procure the missile system as soon as possible, which according to Russia will be in 2019.
But Turkey's interest in the Russian missile system spooked its Western NATO allies, for technical and political reasons.
"In the technological sense, the S-400 would certainly be a step forward [for Turkey], but it's not necessarily in the best interest of NATO to have that weapons system integrated within its broader architecture," Brand said.
The S-400 could lead to a potentially dangerous situation, Brand explained.
"When you look at the Russian S-400 system, especially in a NATO structure, there's a scale of difficulty when integrating it into the bigger defence system," Brand told Al Jazeera.
"If you take it as a very benign situation, the simplest scenario is that its data might not be able to be incorporated into the defensive architecture that is currently used by NATO. That's probably the best worst-case scenario."
NATO relies heavily on several systems working together in a larger network.
"[Adding the S-400] might complicate the picture, it might pollute the view that bigger system is giving you."
But, potentially more harmful, there is the risk that Russia has ill intentions, Brand said.
"What kind of contracts would be in place with Russian technicians taking care of the S-400, for example, would Russian maintenance personnel have access to [NATO] data?
"The worst-case scenario is that there might be vulnerabilities associated with that system that could be exploited by a potential adversary.
"Plugging it in could potentially actively compromise your own defensive network."
For India, Saudi Arabia and Qatar, who are not part of an alliance such as NATO, buying a system like the S-400 would lead to fewer technological issues, but they could risk diplomatic and economic repercussions from the US.
In 2017, the US implemented the Countering America's Adversaries Sanctions Act (CAATSA) in a response to alleged Russian interference in the 2016 US presidential elections and military involvement in both Ukraine and Syria.
CAATSA allows the US to act against individuals, companies or countries that are "disturbing international security".
Yarno Ritzen / Al-Jazeera