US Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, sits in the cockpit of a Su-27 fighter at a People's Liberation Army Air Force base in Jining, Shandong province, on Tuesday. Ng Han Guan / Associated Press

HANGZHOU / BEIJING - Top US military officer Mike Mullen praised the transparency of the Chinese military after visiting air force and army bases in East China on Tuesday.

"I appreciate them showing me this place," said Admiral Mullen, chairman of the US Joint Chiefs of Staff, after touring a base of Division 19 of the People's Liberation Army (PLA) Air Force in Jining, Shandong province, stationed mostly with Su-27 fighters that China purchased from Russia and has upgraded.

The arrangement of the visit "is a very positive step", Mullen said. General Ma Xiaotian, deputy chief of the General Staff of the PLA, accompanied Mullen's entourage.

Mullen sat in the pilot's seat of a Su-27 and talked with the pilot. The admiral, who has spent most of his life in the US Navy, then told reporters: "I feel more like a pilot." He later visited an army base near Hangzhou, the capital of Zhejiang province, where he was shown a simulated anti-terror exercise.

"We still just have the beginning. The relationship is just recently renewed, so we have a long way to go and the leaders made a commitment to that, so I'm actually confident in the future military-to-military relationship," Mullen said.

Mullen will visit a submarine base of the East China Sea Fleet on Wednesday, according to Qian Lihua, director of the Foreign Affairs Office of the Ministry of National Defense.

Qian told reporters that Mullen proposed to see a certain type of submarine at the base, adding that the admiral saw the same type of submarine in 2008 at the North China Sea Fleet.

Major modifications have been made to the type and "I think he will feel satisfied tomorrow", said Qian.

Mullen is in China as a guest of General Chen Bingde, chief of the General Staff of the PLA, for a four-day visit wrapping up on Wednesday when he will leave for the Republic of Korea and Japan.

Mullen was given a high-level reception in Beijing. On Sunday, he was shown around the Second Artillery Force Headquarters, a strategic missile force that controls the country's nuclear weapons.

Mullen was the first US military officer to see the sophisticated equipment at the headquarters, previously visited by three US military leaders.

At a meeting between Mullen and Chen on Monday, their talks dealt with sensitive issues, "which shows the maturity of our relationship and our willingness to overcome differences and increase consensus", Qian said.

"We sincerely exchanged views on our differences this time. I believe that as time goes by, some differences will be put aside, and some will be gradually resolved," Qian said.

Mullen's visit "shows our willingness and sincerity to open up to the outside", Qian said.

He said that foreign and domestic media would be invited to visit a military base in Beijing ahead of Aug 1, the anniversary of the founding of PLA.

Zhao Weibin, a researcher at the Academy of Military Science under the PLA, said Mullen's visit was a big step forward in the transparency of the Chinese military. "They (the US) must have noticed it," Zhao said.