TOKYO (Reuters) - Japan on Monday ordered three C-130 military transport planes to an air base in east Africa to prepare to evacuate Japanese trapped by fighting in South Sudan’s capital, Juba.

“We want to have the aircraft on standby as soon as possible to conduct any evacuation,” Japan’s Minister of Defence Gen Nakatani said after issuing the order.

“The situation there is very fluid.”

Japan’s Chief Cabinet Secretary Yoshihide Suga said earlier some 47 government aid workers had been ordered back to Japan with between 20 to 30 other Japanese civilians in the capital.

The three transport planes would stand by at Japan’s Self Defense Force base in Djibouti, about 3,000 km (1,865 miles) east of Juba.

While Japan has chartered commercial aircraft and used the prime minister’s Boeing 747 jumbo in the past to evacuate Japanese in danger overseas, it would be the furthest and only the second rescue mission by military aircraft.

The rescue would be another sign that Japan’s defense force is increasing its ability to conduct operations far from home, as the government considers a relaxation of constitutional constraints on the military.

A contingent of 350 Japanese army engineers in South Sudan, who are rebuilding roads and other infrastructure as part of a peace keeping operation, will remain for now, Nakatani said.

At least 272 people have been killed in renewed fighting in South Sudan which erupted on Sunday.