Treasury's Lew says U.S. will hit debt ceiling around November 5

In a letter to U.S. Congressional leaders, Lew said the federal government would likely have less than $30 billion in cash at that point, straining its ability to pay its obligations.

"I respectfully urge Congress to take action as soon as possible and raise the debt limit," Lew said.

The federal government is currently scraping just under its $18 trillion legal debt cap, with political wrangling over fiscal policy putting Washington at risk of not being able to pay its bills.

Lew said that the latest corporate and individual tax receipts received by the Treasury were lower than previously projected and trust fund investments higher, resulting in a net decrease in money available to the U.S. government.

While Congress on Wednesday averted a government shutdown by passing a stop-gap measure to extend funding to federal agencies until mid-December, there has yet to be a deal reached on addressing the nation's debt limit.

Earlier this week, U.S. House Speaker John Boehner left open the possibility of advancing an increase to the debt limit before he resigns from Congress on Oct. 30.

Analysts and officials have warned that missing payments could lead to economic calamity. The Treasury already came close to missing payments in 2011 and 2013 when Congress delayed increasing the borrowing limit.

(Reporting by Lindsay Dunsmuir and Jason Lange; Editing by Peter Cooney, Bernard Orr)