The first planeloads of US aid for the Russian wildfire tragedy arrived in Moscow yesterday as firefighters battled to contain a fire still raging close to a top secret nuclear facility.

Officials said that nationwide the area ablaze was almost a quarter that of a week ago but there appeared to be little progress in reducing the size of the fire close to Russia’s main nuclear research centre in Sarov.

Two US Air Force C-130 planes touched down at Vnukovo airport in the early hours of the morning, followed by a charter flight from California ordered by Governor Arnold Schwarzenegger, state television and the foreign ministry said.

“We will always remember this gesture, this arm that was extended to us at a very difficult time,” the deputy head of the international department of the Russian emergencies ministry, Valery Shuikov, said at the airport.

Two additional C-130 flights were expected in the “next days”, the Russian foreign ministry said in a statement. Another charter is also expected this week.

“We acknowledge and assess positively the approach of the American side,” the ministry said. “Such steps fully correspond to the spirit of partner-like constructive relations between our countries.”

According to the US State Department, the total value of the support from Russia’s Cold War-era ex-foe is around $4.5 million.

The delivery follows telephone talks between US President Barack Obama to his Russian counterpart Dmitry Medvedev.

The emergencies ministry said there were still 480 fires in Russia covering an area of 56,000 hectares, a quarter of the area of almost 200,000 hectares reported at the peak of the crisis and down around 10,000 hectares from last Friday.