Russia has been pitching a rival missile platform that costs half of those made by US companies, reports CNBC, which has resulted in several countries dealing with the Kremlin "despite the potential for blowback."

Sefa Karacan | Anadolu Agency | Getty Images

The Russian S-400 mobile long-range surface-to-air missile system costs around $500 million, vs. the $1 billion price tag for a US-made Raytheon Patriot Pac-2 battery, while a THAAD battery made by Lockheed Martin costs just about $3 billion, according to people with first-hand knowledge of a US intelligence assessment.

Nearly 13 countries have expressed interest in buying Russia's S-400, a move that could trigger potential U.S. sanctions under the Countering America's Adversaries Through Sanctions Act, which President Donald Trump signed in August 2017. In September, the U.S. slapped sanctions on China for buying fighter jets and missiles from Russia. However, the U.S. could grant sanction waivers. -CNBC

Turkey, meanwhile, may be hit with US sanctions over their decision to purchase the S-400 defense system, which the United States says poses a risk to its F-35 fifth generation stealth fighter platform.

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Meanwhile, India called the United States' bluff over sanctions in late Ocotber, standing its ground in its decision to buy the S-400.

One of the reasons Russian systems are generally considered less expensive than their American counterparts is because they don't include pricey ongoing maintenance.

"When foreign militaries buy American, above and beyond the purchase, they are buying a partnership with the U.S. military," Andrew Hunter, director of the Defense-Industrial Initiatives Group at the Center for Strategic and International Studies, told CNBC. "And that plus the maintenance and technical assistance is a big part of the cost difference."

The S-400 system made its debut in 2007, succeeding the S-200 and S-300 missile systems. According to CNBC, "the Russian-made S-400 is capable of engaging a wider array of targets, at longer ranges and against multiple threats simultaneously," vs. US-made systems.

In terms of capability, one source noted that while there is no perfect weapon, the S-400 eclipses even THAAD, America's missile defense crown jewel. When asked why nations seek to buy the S-400 instead of America's Patriot or THAAD systems, one of the people with knowledge of the intelligence report explained that foreign militaries aren't willing to stick with the cumbersome process of buying weapons from the U.S. government. -CNBC

"Many of these countries do not want to wait for U.S. regulatory hurdles," said a CNBC source with first hand knowledge of the assessment. "The S-400 has less export restrictions and the Kremlin is willing to expedite sales by skipping over any regulatory hurdles."