* Stocks tumble in China after margin rules tightened
* Crude futures edge up in volatile trade
* Yen hits lowest since 2002 versus U.S. dollar (Updates prices)
By Rodrigo Campos
NEW YORK, May 28 (Reuters) - The U.S. dollar on Thursday hit its highest against the yen since 2002 while stocks fell after Chinese brokerages tightened margin rules and the IMF head played down talk of an imminent deal to keep Greece afloat.
U.S. crude oil futures edged up but were on track for a weekly decline following 10 weeks of gains.
A Greek government official had sparked speculation late on Wednesday that a deal to aid Athens had been drawn up. But a string of denials by top European officials was followed by one from the head of the International Monetary Fund, Christine Lagarde, as G7 leaders met in Germany.
“We are all in the process of working towards a solution for Greece, and I would not say that we already have reached substantial results,” she said in an interview on German television.
“Things have moved, but there is still a lot of work to do,” Lagarde said, adding she believed Greece would fulfil its commitments.
Stocks fell on Wall Street, tracking declines in Europe on worries over Greece, though they were off the session lows. In China, indexes plummeted 6 percent after more brokerages tightened margin trading requirements in a move seen aimed at curbing risks in a red-hot equity market.
“Greece is playing a major role in our markets at this point,” said Paul Mendelsohn, chief investment strategist at Windham Financial Services in Charlotte, Vermont.
He said he expects increased volatility in the short term but “whether we are going to move in any direction remains to be seen.”
The Dow Jones industrial average fell 43.94 points, or 0.24 percent, to 18,119.05, the S&P 500 lost 3.23 points, or 0.15 percent, to 2,120.25 and the Nasdaq Composite dropped 9.91 points, or 0.19 percent, to 5,096.68.
The pan-European FTSEurofirst 300 index fell 0.5 percent.
Japan’s Nikkei bucked the trend, rising for a 10th session on the back of a weaker yen.
The Japanese currency touched its weakest since 2002 against the U.S. dollar, at 124.46 yen. It was last down 0.3 percent on the day just under 124. The euro gained 0.3 percent to $1.0931 and the dollar index fell 0.4 percent after rising 1.4 percent in the previous two sessions.
“I see the dollar trade probably continuing at this point since we’re the only ones moving toward a tightening bias,” said Windham Financial’s Mendelsohn.
“Greece is the wild card in terms of what will happen to the euro.”
In government debt markets, U.S. 30-year Treasury bonds prices were last down 10/32 in price to yield 2.8903 percent, from 2.875 percent late on Wednesday.
U.S. three-year notes were last up 3/32 in price to yield 0.9517 percent, from 0.989 percent late Wednesday. Benchmark 10-year notes were flat, their yield at 2.135 percent.
Front-month Brent rose 0.9 percent to $62.59 a barrel and U.S. crude futures rose 0.4 percent to $57.75.
Gold was little changed near $1,188 an ounce, spot silver dipped 0.2 percent on the day and copper rose 0.45 percent. (Reporting by Rodrigo Campos; Editing by James Dalgleish)