The sophisticated Chinese weaponry paraded past Tiananmen Square on Tuesday, including a new hypersonic missile and a stealth combat drone, sent a clear message to Washington: In military terms, the U.S.’s technological advantage over China is shrinking fast.

The display, marking the 70th anniversary of Communist Party rule in China, highlighted the People’s Liberation Army’s growing emphasis on its missile force, as well as on unmanned systems and electronic warfare, defense experts said.

One highlight of the parade that took many defense experts by surprise was a pair of large unmanned underwater vehicles, or UUVs, that were displayed for the first time.

“The rolling out of this large UUV is significant as only a few major powers have managed such programs,” said Collin Koh, research fellow at the S. Rajaratnam School of International Studies in Singapore.

He said it could be used for defense or offensive purposes.

“Protection of Chinese strategic sea-based nuclear assets is one such plausible use,” he said. “Offensive missions could entail deploying such drones for discreet intelligence gathering close to foreign shores or foreign naval formations in distant waters.”