The number of Americans filing first-time claims for unemployment benefits dropped last week for the fourth straight week, government data revealed Thursday.

In the week ending Oct. 3, initial claims sat at 521,000, a decrease of 33,000 from the previous week's figure, the U.S. Department of Labour said. Economists polled by Thomson Reuters were expecting 540,000 new claims.

That's the fewest initial jobless claims since the first week of January.

Existing jobless claims also fell by a more-than-expected 72,000, to sit at 6,004,000 for the week ending Sept. 26. That's the lowest rate since March, and economists were expecting a figure of 6.1 million.

It's not clear to what extent the decrease in jobless claims was due to the unemployed finding new jobs, and how much can be attributed to still-jobless Americans simply running out of benefits.

Most states offer 26 weeks of benefits, but earlier this year, Congress approved federally funded extensions of up to 53 weeks in some cases.

As recently as last month, Democratic Congressman Jim McDermott brought forward a bill that would offer an additional 13 weeks of benefits for more than 300,000 jobless people who live in states with unemployment rates of at least 8.5 per cent.

Most of those people were set to run out of benefits by the end of September.

On a not seasonally adjusted basis, the number of people collecting extended federal benefits rose by 68,000 to 3.79 million, the agency said.

Including those federal programs, the number of people claiming benefits of any kind in the week ending Sept. 19 was 9.36 million, not seasonally adjusted, down from 9.42 million in the previous week.