The Pentagon confirmed Thursday that Chinese nationals fired lasers near a military base in east Africa against U.S. military aircraft in the region, injuring several pilots.

Pentagon Press Secretary Dana White said the U.S. government made diplomatic protests to the Chinese government over several recent incidents of laser firings near China's first overseas military base at Djibouti.

"These are very serious incidents. There have been two minor injuries. This activity poses a threat to our airmen," White told reporters.

"We have formally demarched the Chinese government, and we've requested that the Chinese investigate these incidents," she added.

The number of incidents is "more than two but less than ten" and the laser firings took place in recent weeks, White said.

White said the Pentagon is confident that Chinese nationals were behind the laser firings but did not elaborate on the intelligence linking Beijing to the incidents.

She declined to speculate on the Chinese motive behind the laser attacks.

"I believe there have been cases where this has happened previously," White said. "But what this started was these last few weeks we decided to become very serious about it, and we have demarched the Chinese, and we've asked for the investigation."