Asian traders shifted cautiously on Tuesday with Chinese stocks coming under renewed pressure, while concerns grew about the future of the much-vaunted US tax reforms.
After months of gains across global equities, investors are taking a step back on unease that some valuations may be too high.
In early trade Shanghai was down 0.1 percent, extending a sell-off that has seen the benchmark index lose more than three percent since Wednesday. Hong Kong shed 0.3 percent.
Mainland dealers have been spooked by Beijing's crackdown on risky dealing, while a warning from authorities last week about the sharp rise in one of the country's best-performing stocks added to worries.
Analysts have noted a lack of intervention by state-backed firms to support key issues, indicating authorities are willing to see prices fall as they look to cool the market.
Greg McKenna, chief market strategist at AxiTrader, also pointed out that several data reports have undershot expectations recently, raising worries about the Chinese economy.
"That means the first two weeks of December, when we get the next monthly update on the Chinese economy, are going to be very important," he added.
Elsewhere in Asia, Tokyo ended the morning session up 0.2 percent while Sydney was up 0.1 percent.
Singapore was flat and Manila shed one percent.
'Tough, tough time'
Seoul was 0.4 percent up, reversing an early sell-off that came on the back of reports that a flurry of activity was detected at a North Korean missile base, raising concern it may be preparing a new missile test.
The news also sent the yen rallying against the dollar initially on a chase for safety, though it gave back the gains later in the morning.
Eyes are now on Washington where senators are expected to vote on Donald Trump's tax-cut plans but there are fears his Republican party might not be able to muster enough votes to push it through.
While the successful passage of the bill would likely fire up global markets, analysts fear its failure could lead to a correction.
Expectations Trump would push through his market-friendly measures of cutting taxes, ramping up infrastructure spending and cutting red tape have helped fuel a global rally.
However, Republican infighting -- at least two senators are presently ready to vote it down -- has led to concerns that the tax reform could collapse in similar fashion to their overhaul of healthcare.
"It's not going to be easy. This is going to be a tough, tough time," senate finance chairman Orrin Hatch, the chamber's chief tax writer, said according to Bloomberg News.
This week sees a slew of other potentially market-moving evens, with the congressional hearing for Jerome Powell, Trump's pick as the next Fed boss, while current governor Janet Yellen is also due to speak and official US growth figures are released.
- Key figures around 0230 GMT -
Tokyo - Nikkei 225: UP 0.2 percent at 22,533.72 (break)
Hong Kong - Hang Seng: DOWN 0.3 percent at 29,605.94
Shanghai - Composite: DOWN 0.1 percent at 3,381.19
Euro/dollar: UP at $1.1900 from $1.1899 at 2140 GMT
Pound/dollar: UP at $1.3322 from $1.3321
Dollar/yen: UP at 111.30 yen from 111.09 yen
Oil - West Texas Intermediate: DOWN 27 cents at $57.84 per barrel
Oil - Brent North Sea: DOWN 13 cents at $63.71 per barrel
New York - DOW: UP 0.1 percent at 23,580.78 (close)
London - FTSE 100: DOWN 0.4 percent at 7,383.90 (close)