Protests against American military presence in Japan continued on Saturday, as the country’s defense minister lodged a formal complaint over the latest case of alleged murder and rape of a young Japanese woman by a US military base employee.

Gen Nakatani visited the US Kadena Air Base on Saturday to formally protest the alleged crime to its commander Lt. Gen. Lawrence Nicholson.

"I deliver a strong message of regret and at the same time make a protest,” he said as cited by the public broadcaster NHK.

Japanese officials including Prime Minister Shinzo Abe expressed outrage over the latest in a string of crimes, which has been poisoning US-Japanese military ties for decades. The country’s Foreign Ministry filed a formal complaint over the case as well.

Critics of the deployment of US troops in Japan complain of the crimes committed by American personnel against local residents, environmental damage done by US bases and other negative sides. Okinawa Island hosts roughly half of all American troops in Japan, and sentiment against the arrangement are especially strong there.