The United States has accused China of mounting a campaign of harassment against its forces in the Horn of Africa by using military grade lasers to disorient its fighter pilots.

The Pentagon issued a formal complaint, demanding that Beijing investigate a series of incidents in recent weeks in the skies above Djibouti, where China and the United States operate military bases just miles apart.

The allegations, including a claim that two US air force pilots suffered eye injuries during one laser attack, drew swift Chinese denials, China’s defence ministry dismissing them as being “in complete contradiction of the facts”.

The military confrontation between the two powers is one of the most significant outside the South China Sea and the most serious so far in Africa, where Beijing has worked assiduously to project its growing economic and geopolitical heft.

A row had appeared almost inevitable since Djibouti stunned Washington by allowing China to build its first overseas military base, completed late last year, within 18 miles of Camp Lemonnier, headquarters of US Africa Command.