China's president offered condolences Friday to the families of 46 South Koreans killed in a warship blast near the tense inter-Korean border, as ships searched for any signs the North was to blame.
President Hu Jintao expressed sympathy before summit talks with President Lee Myung-Bak on the sidelines of the opening of the Shanghai World Expo.
"I also want to address the tragic loss of your country's warship. To those who died and to their families, please let them know we grieve with them," Hu said, according to a Chinese pool report.
Lee's spokesman has said the sinking was expected to be raised.
China, North Korea's sole major ally and its key source of food and energy, is seen as one of the few nations able to put pressure on the North.
A mystery explosion ripped a 1,200-tonne South Korean corvette the Cheonan apart on March 26 near the disputed border.
South Korea has not openly blamed its communist neighbour but suspicions of a North Korean torpedo attack are growing.
Further souring relations, the North Friday ordered some 40 South Korean staff to leave a jointly-run mountain resort in protest at Seoul's refusal to restart lucrative tours there.
Seoul's defence minister has said a heavy torpedo was among the likeliest causes of the underwater explosion.
Officials have said a military response has not been ruled out if the North is found responsible, but the case would likely be taken to the United Nations Security Council.
In that case, China's role as a veto-wielding permanent Council member would be crucial in securing any binding resolution against the North.
It backed tougher UN sanctions after the North's second nuclear test last May. But some analysts say Beijing would not likely support punitive steps over the sinking unless firm proof of Pyongyang's involvement emerges.
In search of that proof, 10 ships are scouring the scene of the tragedy but have found nothing conclusive yet.
The defence ministry told parliament's defence committee it has asked for chemical analysis of 297 salvaged items. So far, 143 items have been tested but no traces of explosives have been found.
Defence Minister Kim Tae-Young told the legislators a piece of aluminium which was not from the sunken ship had been retrieved, but did not elaborate.
Analyst Daniel Pinkston, of the International Crisis Group think-tank, said the sinking underscores the importance of reconvening stalled six-party nuclear disarmament talks.
"To allow this incident to destroy the six party talks -- I think it is exactly what North Korea would like to see," he told a forum.
Baek Seung-Joo of the Korea Institute for Defence Analyses said military elements in the North are gaining ground over those wanting negotiations.
"Under these circumstances, as inter-Korean relations are deteriorating and the six-party talks are at a standstill, the North may carry out a third nuclear test."
At the Seoul-funded Mount Kumgang resort the North's officials Friday told some 40 South Koreans to leave by Monday morning, according to the South's unification ministry.
Last week the North confiscated five properties owned by the Seoul government at the resort, and this week it has been barring access to privately owned premises there.
The sanctions-hit state is angry at the Seoul government's refusal to restart tours, suspended in July 2008 after North Korean soldiers shot dead a Seoul housewife there.
The programmes once earned it tens of millions of dollars a year.
Copyright 2010  AFP Asian Edition
