NEWPORT Rhode Island (Reuters) - Russia and China are trying to close the technology gap with the U.S. military and developing weapons systems that appear designed to counter traditional U.S. advantages, Defense Secretary Chuck Hagel said on Wednesday.

Hagel was speaking before a NATO summit expected to bring Russia's souring relations with the West into sharp focus and the goals of NATO allies to strengthen defense spending.

Hagel said the Pentagon was renewing a push to revamp how it works with the defense industry. The goal, he said, was to promote greater innovation needed to preserve America's technological edge, even at a time of tighter budgets.

"While the United States currently has a decisive military and technological edge over any potential adversary, our future superiority is not a given," Hagel told a defense industry forum in Rhode Island.

U.S. defense officials have watched as Moscow and Beijing have tested a string of sophisticated weapons, from radar-evading aircraft and anti-ship missiles that fly many times the speed of sound, to integrated air defenses.

While the Defense Department's spending of around $500 billion is still more than the next six or seven countries combined, research and development spending has fallen more than 20 percent since President Barack Obama took office.

In contrast, China and Russia have been rapidly increasing their security spending and have passed new technological milestones in recent years.

"China and Russia have been trying to close the technology gap by pursuing and funding long-term, comprehensive military modernization programs," Hagel said.

"They are also developing anti-ship, anti-air, counter-space, cyber, electronic warfare and special operations capabilities that appear designed to counter traditional U.S. military advantages."

Leading U.S. weapons manufacturers, including Lockheed Martin Corp, Boeing Co and Northrop Grumman Corp, have urged the Pentagon to continue investing in research and development of new weapons and technologies despite less military spending.

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Frank Kendall, the Pentagon's chief weapons buyer, said he had been asked to lead an initiative that would take a longer-term look at research and development spending.

"When you cut R&D you are delaying modernization. Period," Kendall told the ComDef 2014 defense conference in Washington.

(Reporting by Phil Stewart, Andrea Shalal-Esa and David Alexander; Editing by Grant McCool)