Japan's Prime Minister Shinzo Abe said Sunday he hoped to meet the Chinese and South Korean leaders soon to improve relations strained by separate territorial rows.

But his ruling party also pledged the same day to push for changes to Japan's pacifist constitution - a move likely to stir unease in both the countries, which were among victims of Tokyo's 20th century militarism."I am in the same generation as the two new leaders," Abe told an annual convention of his Liberal Democratic Party (LDP), referring to Chinese President Xi Jinping, 59, and South Korean President Park Geun-Hye, 61.

The 58-year-old Abe became prime minister in December for a second time when his conservative party secured a landslide election victory, while Tokyo was locked in disputes with Beijing and Seoul over island chains. "For prosperity and stability in the region, it is necessary for the three of us to build mutual understanding," Abe told the convention. "I want to say that Japan's door is always open toward China," said Abe, who was previously premier from 2006-2007.

But earlier in the day, the premier urged graduates of the National Defence Academy to guard the country against "provocations", an apparent reference to the row with Beijing over sovereignty of a Tokyo-controlled island chain.Meanwhile, China's appointment of a former ambassador to Japan as its foreign minister is unlikely to soften Beijing's position over islands at the centre of a dispute with Tokyo, Japanese media said on Sunday.

Wang Yi's new job was approved on Saturday by the National People's Congress, Beijing's rubber-stamp parliament, which also promoted his predecessor Yang Jiechi to a member of the State Council, China's cabinet."Although (Wang) is fluent in Japanese, well versed on Japan and has contacts with the Japanese political world, it is contrarily damaging for him to be seen at home as sympathetic to Japan," the newspaper Sankei Shimbun said.

The conservative daily noted that the outgoing foreign minister had repeatedly talked tough against Japan, particularly over the Tokyo-administered Senkaku islands in the East China Sea, which Beijing also claims and calls the Diaoyus."Therefore, it is seen difficult to improve the Japan-China ties at an early date," Sankei said.The Jiji Press news agency quoted a Japanese diplomatic source as saying: "Being well informed on Japan, he may rather take a harder line as he takes care not to be criticised for being weak-kneed."

Wang, 59, served as ambassador to Japan from 2004 to 2007 and was also a diplomat in China's embassy in Tokyo from 1989 to 1994. He has been in charge of Taiwan affairs on the State Council since 2008.Japanese media also pointed out that when Wang was ambassador in Tokyo he helped mend the bilateral ties strained through visits by then prime minister Junichiro Koizumi to a Tokyo shrine honouring the Japanese war dead, including World War II leaders, amid protests from neighbouring countries.

"It is apparent that the government of Xi Jinping is considering treating the Japan-China ties carefully," the Asahi Shimbun said."His first task will be an attempt to normalise the Japan-China dialogue which has been mired in an awkward state amid a chain of mistrust and to pave the way for a Japan-China summit meeting," the influential daily said.