US shares gained ground at the open on Monday following another dismal week to end September, but analysts warn that uncertainty continues to rattle investors.

After the worst month for the market in 20 years, the main stock indices retraced some of Friday's losses, with the Dow Jones adding 1.2 percent to 29,079 about 15 minutes into the trading day.

The S&P 500 gained 1.1 percent to 3,625, while the Nasdaq rose 0.8 percent to 10,654.

"These are not huge gains, but that does not make them any less welcome – certainly not after the month that just concluded," said Briefing.com analysts Patrick J O'Hare.

"The understandable question on everyone's mind is, will they last? After all, there is some riptide below the surface."

Investors remain concerned about the Federal Reserve's aggressive policy path as it battles to bring down the highest inflation in 40 years, as well as the impact of rising interest rates on the financial sector.

Global banking giant Credit Suisse has been trying to reassure markets that it has sufficient capital to weather a planned restructuring, but jitters sent the stock sinking on Monday.

Meanwhile, Tesla shares dropped 7.4 percent after the electric carmaker on Friday reported that while vehicle deliveries increased in the latest quarter, the total was at the low end of expectations. (AFP)