The rout appeared to slow on Wednesday as Chinese blue chips closed up 0.2%, but the Shanghai Composite Index ended 0.6% down, its lowest close since March 10.
After Asian markets closed, focus quickly turned to the Fed.
Investors are primed for any hints on when the central bank will start reducing its purchases of government bonds and any new insight into its views on inflation and economic growth.
"In the background, you have the ripple effect of the Chinese crackdown and a lot of companies reporting today, but the Fed is the major event," said Francois Savary, chief investment officer at Swiss wealth manager Prime Partners.
"Are we going to get a timetable on tapering Is it going to be clearly announced"
The statement from the Fed policy meeting is due at 2 p.m. EDT (1800 GMT), with a news conference by Chairman Jerome Powell expected half an hour later.
In U.S. stock futures, the S&P 500 e-minis, were 0.1% higher, signalling a recovery on Wall Street after stocks on Tuesday retreated a little from the record highs set earlier in the week as ripples from China spread.
In U.S. trading, the Nasdaq Golden Dragon China benchmark of Chinese tech stocks listed in New York fell another 6%, taking its losses since Friday past 20% and wiping $500 billion off its value.
Chinese state-run financial media urged calm on Wednesday after a roiling of stocks in the technology, property and education sectors in recent days.
Hong Kong's benchmark added 1.5%, but remained near nine-month lows.
MSCI's broadest index of Asia-Pacific shares outside Japan was 0.3% firmer after three straight sessions of losses.
"The moves are being driven by general risk appetite. On Monday and Tuesday Chinese stocks led everything lower but today there is a bit of pause for assessment," said Colin Asher, senior economist at Mizuho in London.
"There were question marks over the global implications of the recent moves by Chinese authorities but the macro impact on most countries is limited."
With investors holding off on major bets before the Fed meeting, the dollar made marginal gains after earlier being pinned down by demand for safe-haven currencies.
The U.S. dollar index moved into positive territory after trading lower in Asian hours, with the greenback last up 0.1% at 92.575.
The currency has had a month-long rally after a hawkish shift from the Fed in June.
The Chinese yuan edged back from three-month lows. It had its worst day since October on Tuesday.
The yield on benchmark 10-year Treasury notes strengthened to 1.2644%, up from the U.S. close of 1.234%.
Greek government bond yields hit new lows on Wednesday as the promise of more central bank largesse to counter the Delta coronavirus variant pushed up demand for even the lowest rated euro zone countries.
Greece's benchmark 10-year government bond yield dropped a basis point to a seven-month low of 0.61%.
Oil prices rose as industry data showed U.S. crude and product inventories fell more sharply than expected last week, outweighing worries that surging COVID-19 cases would curb fuel demand.
U.S. crude rose 0.52% to $72.02 a barrel and Brent crude rose 0.31% to $74.71 per barrel.
Gold held steady, with spot prices flat at $1,797.97 near the key psychological level of $1,800, while Bitcoin rose around 3.2%, trading just above $40,000.
(Reporting by Tom Arnold in London and Alun John in Hong Kong; Additional reporting by Sujata Rao; Editing by Ana Nicolaci da Costa, Kim Coghill, Catherine Evans and Timothy Heritage) ((email@example.com;))