* Yellen says considerable slack in U.S. labour market
* Putin calls for pro-Moscow separatists to postpone a secession vote
* China trade data in focus in Asia
TOKYO, May 8 (Reuters) - Asian shares drew a measure of comfort from dovish comments by the U.S. Federal Reserve chief and signs of easing tensions in Ukraine after Russian President Vladimir Putin called on pro-Moscow separatists to postpone a succession vote.
Nikkei share average rose 0.7 percent while MSCI's broadest index of Asia-Pacific shares outside Japan ticked up 0.15 percent, inching away from five-week lows hit on Wednesday.
In Asia, markets will be focused on China's trade data after exports unexpectedly fell for the second straight month in March and import growth dropped sharply.
Another poor outcome is likely to depress risk appetite, with economists expecting slight falls in both imports and exports for April from a year earlier.
Intensifying concerns about weak manufacturing and slowing growth in the world's second-largest economy have buffeted global markets in recent months.
The early impetus came from Fed Chair Janet Yellen's testimony to Congress, which helped U.S. shares reverse earlier losses to end in positive territory.
Yellen repeated her stance that the economy was still in need of lots of support given the "considerable slack" in the labour market.
"Yellen ... put her emphasis on the ways in which the economy and labour market were still falling short of the FOMC's goals. She also emphasized risks to the economy from a potential continuation of the recent 'flattening out' of housing activity," said Barclays analysts in notes to clients.
"The clear implication is that accommodative policy will be needed for a long time."
The Dow Jones industrial average rose 0.7 percent while the S&P 500 gained 0.6 percent.
Emerging market shares also held firm, with Brazilian shares hitting six-month highs and Mexican stocks at their highest in more than three months.
Yellen's remarks also kept the 10-year U.S. Treasuries yield at 2.590 percent, near Monday's three-month low of 2.572 percent.
Adding to the improved mood, Putin called on pro-Moscow separatists in Ukraine to postpone a vote on secession just five days before it was to be held.
In what could be a breakthrough in the worst crisis between East and West since the Cold War, Putin also announced he was pulling Russian troops back from the Ukrainian border.
The dollar-denominated Russian shares hit five-week high.
The euro traded flat at $1.3910, not far from Tuesday's two-month high of $1.3952 ahead of the European Central Bank's policy meeting later in the day, with a majority of investors expecting no policy change.
A Reuters poll of over 60 foreign exchange strategists showed on Wednesday that they think the euro needs to reach $1.42 before the ECB takes any action to weaken the currency. Still, the vast majority believe that such action is unlikely to happen.
The British pound held near a five-year high against the dollar on rising expectations the Bank of England could tighten its policy before the the Fed, probably early next year.
With risk sentiment improving slightly, the yen stepped back from three-week high of 101.43 yen to the dollar set on Wednesday, and traded at 101.90 yen.
(Editing by Shri Navaratnam)