* Improper to set final date for gas supply pact - ambassador
* Says ESPO crude exports to china at 6.25 mln T as of June 1
* Sino-Russian trade forecast to reach $70 bln in 2011 (Adds details, background)
By Jim Bai and Tom Miles
BEIJING, June 10 (Reuters) - China and Russia are still negotiating a massive natural gas supply pact and it would be inappropriate to set a date for the companies involved to conclude the deal, Russia's ambassador to China said.
"The size of the deal is huge ... and there are two documents -- an agreement between the two governments and a long-term contract between the companies -- to be agreed on. It's an arduous task and it cannot be done before a certain date," Sergey Razov said on Friday. "Many principles have been agreed, and some important issues have yet to be settled."
"As a seller, Russia wants higher gas prices; as a buyer, China hopes to get lower prices," Razov told reporters at a press briefing in Beijing. "We hope the negotiations are finished as soon as possible."
On May 31, Russia said it would finalise a major gas supply deal with China in time for a visit in mid-June by Chinese President Hu Jintao, wrapping up years of talks to open a new export route to the world's biggest energy market.
Russian Deputy Prime Minister Igor Sechin said he had reached a broad agreement at a meeting in Moscow with his counterpart Wang Qishan to supply China with 68 billion cubic metres (bcm) per year of gas over 30 years.
State-controlled Russian gas export monopoly Gazprom has invited China National Petroleum Corp (CNPC) to continue discussions on the gas supply deal next week as political pressure to wrap up talks mounts.
Razov also said Russia's East Siberia-Pacific Ocean (ESPO) pipeline had supplied China with 6.25 million tonnes of crude oil from January 1 to June 1, in line with earlier plans by the two countries. He did not provide an explanation for the oil price dispute between Russian companies and CNPC, which Interfax said has been resolved.
Razov also said that trade between the two countries could reach $70 billion this year, up from the $59 billion in 2010. (Editing by Chris Lewis)