A former NATO commander raised concerns over the U.S. military's lack of modernization that he believed could help Russia and China push America behind in the list of world's most powerful militaries. U.S. Army Gen. Wesley Clark's comments came days after President Donald Trump said he would boost the country's military spending by $54 billion.

"We've taken it for granted. For 25 years we had the best ... armed forces in the world," Clark said Sunday, in an interview with John Catsimatidis on New York's AM 970. "The United States has mostly put its military modernization on what's called a 'warm idle.' We've done some research, we’ve looked at what we need. But we have not bought the stuff that is cutting-edge."

Currently, the U.S. has the world's most powerful military, with more than 1.4 million troops, 13,000 war planes, and nearly 9,000 tanks. 

"We are spending our money on ordinance, on bombers, on missiles that are blowing holes in the ground and sometimes hitting terrorists," Clark said. "But Russia, they have produced a new generation of armored forces. ... They have a T-14 tank that’s got active protection on it. ... It's the tank we would like to have in 2030. We are that far behind."

Russia has the world's second biggest military, with more than 1 million troops, 3,500 war planes and 15,000 tanks. Moscow's military budget is likely to grow to $41.4 billion by 2020, or about 5 percent of its GDP. In January, Russian Prime Minister Dmitry Medvedev said the country's domestic defense industry will expand through 2025.

Clark also described a new Russian air defense system that is being used by China, which is ranked third with roughly 2.3 million soldiers and 3,000 war planes, saying, "It changes the air-ground dominance where the United States could easily get air supremacy in the past.

"The Chinese have their second aircraft carrier visibly under construction. My sources tell me there will be two more Chinese carriers built in this decade," he added, asserting: "China will have regional air superiority over the United States" without additional defense spending.

While talking about the new military budget, Clark said: "Unfortunately, the new $54 billion (that would be) going into the Defense budget doesn't really deliver sufficient funds to meet the need. ... We need more money than that on a sustained basis."

On Sunday, Chinese Premier Li Keqiang announced that the country will escalate its defense budget by 7 percent — the lowest military spending hike since 2010 — but it would cost Beijing more than $146 billion.