WASHINGTON — The Pentagon official in charge of financing America's current and future wars downplayed concerns that trade disputes were spilling into the industrial base.

"We haven't seen that so far," said Patrick Shanahan, deputy secretary of defense, Wednesday to a small group of reporters.

"As you know, the way I tend to think about that is that these relationships are very complex. They're not monolithic," explained Shanahan, the Pentagon's No. 2 official, adding that the Defense Department works closely with the State, Commerce and Treasury departments to navigate the economics of foreign military sales.

"So while there's an issue maybe over here on one type of trade, you know, it's how do we keep it from spilling over, or in some cases, it's intended to get tied together so that it can create a different form of leverage," he added.

Shanahan's comments come amid intensifying trade tensions between the U.S. and China, the world's two largest economies, and increased sanctions on Russia.

On Friday, Indian Prime Minister Narendra Modi signed a $5 billion deal with Russian President Vladimir Putin for the S-400 missile system, a deal that may peeve Washington but fall short of financial consequences.

The Russian-made S-400 system is believed to have a longer range than the U.S.-made THAAD missile system and is estimated to cost significantly less.

"The dilemma with India is forever the Indians bought equipment from Russia," Shanahan said before to the deal between New Delhi and Moscow. "So you have to buy spare parts, you have to maintain it and it's not like you cut that off," he added, nothing that Congress is able to provide a waiver for certain military purchases with Russia.