U.S. May employment numbers came out disappointingly weak Friday, leading Goldman Sachs and others to question the sustainability of the economic rebound.

Non-farm payrolls rose a paltry 54,000 last month, vastly undershooting economists’ forecasts of a 165,000 increase. And April’s gain was revised downward to 232,000. The unemployment rate unexpectedly ticked up to 9.1 percent in May from 9 percent a month earlier.

Clearly the labor market is in a precarious state.

These numbers represent a major setback, and they can’t be blamed on temporary woes in the auto sector caused by Japan’s natural disaster, Goldman wrote in a commentary.

And Goldman economists aren’t the only ones in a pessimistic mood.

“This to me is a rational correction in stocks given that economic growth will slow over the next few quarters,” Russ Koesterich, chief investment strategist for BlackRock’s IShares unit tells Bloomberg.

“The jobs report is the last nail in the coffin. It confirms that the economy is dramatically slowing. It tells me that the Fed will be in no rush to tighten monetary policy.”

Other figures in the jobs report weren’t so hot either, the bank’s economists note. Average hourly earnings barely eked out a gain — to $22.98 from $22.92 in April. And the average work week didn’t increase at all — sticking at 34.4 hours.

Put the employment data together with other recent statistics, and it’s clear that the economy is decelerating fast, Goldman maintains.

“After the recent run of weaker-than-expected data, our Current Activity Indicator (CAI) stands at just 1.0 percent for May, down from 1.6 percent in April and 4.2 percent in March.”

GDP growth already plunged to 1.8 percent in the second quarter from 3.1 percent in the first.

"This highly disappointing report is a real shocker," Mohamed El-Erian, co-chief investment officer at bond manager monolith Pimco, told Reuters.

There’s no silver lining in the data, he says.

"It confirms that America has an unemployment crisis that involves worrisome economic, political and social dimensions. . . . It speaks to a large unemployment problem that is becoming increasingly structural, and therefore protracted, in nature."

The stock market didn’t react well to the jobs report either. The Dow Jones Industrial Average dropped almost 1 percent to 12,141 in early trading. Equity markets overseas followed suit.

Julia Coronado, chief U.S. economist for BNP Paribas, agrees. The numbers make it more likely that the Federal Reserve will keep short-term interest rates at almost zero through at least the end of the year, she tells Bloomberg.

To be sure, not everyone sees the economy falling off a cliff.

"It is likely that this will be a soft patch in the coming months but overall it will probably be a soft patch rather than a double-dip recession or something worse," Sean Incremona, an economist at 4CAST, tells Reuters.