* Asian shares hobbled by U.S.-China technology battle
* Spreadbetters expect firmer open for European stocks
* Fed's Powell dismisses concerns about rising debt levels
* Chip-related shares under pressure
* Asian stock markets: https://tmsnrt.rs/2zpUAr4
By Hideyuki Sano and Tomo Uetake
TOKYO, May 21 (Reuters) - Asian shares won some respite on Tuesday after Washington temporarily eased trade restrictions imposed last week on China's Huawei, although fears of a further escalation in tensions kept investors on edge.
Financial spread-betters expect London's FTSE Frankfurt's DAX and Paris's CAC to gain between 0.3% and 0.5% when they open.
MSCI's broadest index of Asia-Pacific shares outside Japan was up by a marginal 0.1% but stayed not far from a four-month low touched on Friday.
It has fallen almost 8% from a nine-month peak hit just over a month ago. Japan's Nikkei average retreated 0.3%.
China's blue-chip CSI300 index jumped 1.4%, a day after it fell to a three-month intraday low as Washington allowed Huawei Technologies Co Ltd to purchase American-made goods in order to maintain existing networks and provide software updates to existing Huawei handsets until Aug. 19. The benchmark Shanghai Composite climbed 1.2%.
Still, an increasingly acrimonious atmosphere between the world's two biggest economies has led investors to abandon any hopes of an early resolution, a sea change from just a few weeks ago when a deal was considered to be within reach.
"With the news around the U.S. and Huawei taking a turn for the worse, it seems that the trade war is increasingly showing signs of becoming a tech war," said Seema Shah, senior global investment Strategist at Principal Global Investors in London.
"The further this trend develops, the bigger the collateral damage will be – particularly in Asia and the U.S., but the ripple effect will be significant across the globe."
In New York, the S&P 500 lost 0.7% while the Nasdaq Composite dropped 1.5%. The Philadelphia Semiconductor Index fell 4.0% to two-month lows.
Huawei suppliers took a hit, with Qualcomm falling 6.0% and Micron Technology 4.0%.
"The determination of the U.S. administration to paralyse China's aspirations to become a technology super power is clear when you consider that its actions against Huawei are not only damaging to China's technology sector, but also the U.S. tech sector," Shah said.
Some U.S. companies, such as Alphabet's Google and Apple Face ID parts supplier Lumentum Holdings Inc, have already started to limit services to Huawei.
Following Washington's Huawei ban, analysts suspect Beijing could take retaliatory measures against U.S. companies, further escalating tensions.
In addition to short-term economic disruptions, it could have huge repercussions for the global economy, said Cliff Tan, Head of East Asian research at MUFG Bank in Hong Kong.
"At a theoretical level, the Trump Doctrine means that in the context of national security, the U.S. government can seemingly go after anybody. That's why in my gut I wondered, has Trump signalled the end of the global supply chain, for at least a few years?," Tan said.
"I think trade diversion creates short-term winners and losers, but the overall impact on innovation may be negative for everyone," he added.
Markets showed scant reaction to a speech by Federal Reserve Chairman Jerome Powell, who dismissed comparisons between the rise of business debt to record levels in recent years and the conditions in U.S. mortgage markets that preceded the 2007-to-2009 economic crisis.
In the foreign exchange market, major currencies were on the sidelines for now.
The euro was under pressure ahead of the European election this weekend but was little moved at $1.1158, off Monday's low of $1.1150, its lowest since May 3.
The dollar was little changed at 110.18 yen, near Monday's two-week high of 110.32 yen.
The British pound was listless near four-month lows, trading at $1.2723, just a stone's throw from Friday's low of $1.2714, as embattled UK Prime Minister Theresa May struggled to pull together a Brexit deal.
The yuan firmed slightly to 6.9030 to the dollar in onshore trade, still not far from a 5-1/2-month low of 6.9188.
The Australian dollar dipped 0.5% to $0.6877 after Australia's central bank governor said he would consider the case for lower interest rates at its June policy meeting.
Oil prices held near multi-week highs as OPEC indicated it was likely to maintain production cuts while escalating Middle East tensions provided further support.
Brent crude futures traded up 0.3% at $72.20 per barrel while U.S. crude futures fetched $63.31 per barrel, up 0.3%. (Additional reporting by Divya Chowdhury; Editing by Sam Holmes and Jacqueline Wong)