The euphoria of last week -- fueled by optimism the US central bank's tightening cycle was over and China's pledges of economic stimulus -- has given way to uncertainty again, as analysts warned the road ahead remained bumpy.

Jobs data over the past few days has reminded traders that while inflation is coming down, the Fed still had a lot of work to make sure it continued to fall in order to hit its two percent target and stay there.

News that jobless claims were still around the lowest levels of the year added to unease, the central bank has warned loosening the jobs market was key to fighting inflation.

That put upward pressure on Treasury yields -- flagging higher Fed rates down the line -- compounding Fitch's decision to cut the United States' gold-standard AAA rating on Tuesday.

Attention now turns to the release of jobs creation figures later Friday, which could play a key role in the Fed's rate decision-making, particularly after officials at the bank said they would be more data-dependent in future.

A forecast-busting reading on private firms hiring spooked investors.

Wall Street sank in response to the higher Treasury yields, extending a sell-off that has marked the week in New York.

And while Asia fared a little better, sentiment remained fragile.

Hong Kong and Shanghai rose, helped by a meeting between the heads of the People's Bank of China and several companies that ended with a pledge for fresh support to the troubled property sector.

The gathering and pledge comes after authorities outlined a number of measures to stimulate the economy, including some aimed at real estate.

"Developers have had some refinancing troubles again recently," Ding Shuang, at Standard Chartered said. "Support will be targeted toward high-quality companies."

Wellington, Manila and Jakarta also rose. 

However, Tokyo, Sydney, Singapore, Seoul and Taipei were in the red.

Analysts said the selling could also be attributable to profit-taking after markets enjoyed a broadly strong July.

SPI Asset Management's Stephen Innes added: "August is commonly perceived as a quiet month.

"Still, this week's risk-off tenor reminds you that the market can swing big on unexpected events due to the low liquidity and tepid trading activity."

Oil prices moved in a tight range after rallying more than two percent Thursday following Saudi Arabia's decision to extend its voluntary oil production cut of 1 million barrels per day for another month.