WASHINGTON (AP) — The Treasury Department on Thursday told Congress that it needs to act by Nov. 3 or the government will be dangerously close to being unable to pay all its bills.

That's a little sooner than Treasury Secretary Jacob Lew said two weeks ago when he set a Nov. 5 deadline. At the time, some GOP lawmakers felt Lew was trying to rush them into approving an increase in the government's $18.1 trillion borrowing limit.

But the Congressional Budget Office brought its predictions in sync with Treasury in a report Wednesday.

Lew said the Treasury thinks the government will have less than a $30 billion cash cushion on Nov. 3 and noted that the government can pay out as much as $60 billion on some days. On Nov. 3, the government would no longer be able to take arcane bookkeeping steps known as "extraordinary measures" to continue borrowing under the cap.

If the government runs out of cash, it cannot meet obligations such as interest payments, Medicare payments and Social Security checks. The government has never defaulted on its obligations, and a severe market reaction would be all but certain if it did.

"In the absence of congressional action, Treasury would be unable to satisfy all of these obligations for the first time in the history of the United States," Lew wrote.

The Bipartisan Policy Center, a Washington think tank, estimates that the actual date of default would fall between Nov. 10 and Nov. 19, depending on the government's cash flows. They include more than $30 billion in outlays for Social Security and federal retirement benefits on Nov. 3.

Financial markets would be sure to act nervously well before then if Congress drags its feet or looks as if it's having difficulty passing a politically difficult debt measure.

Lew's letter comes as closely-held talks on the budget have shown little evidence of progress. Some Republicans hope to win concessions in exchange for a debt increase, but that's unlikely.

With the House GOP conference in turmoil, it will fall to Speaker John Boehner, R-Ohio, to shepherd a debt limit increase. Senate Majority Leader Mitch McConnell, R-Ky., has repeatedly said the GOP-controlled Congress will not permit a first-ever default.

Early last year, Boehner and McConnell both supported a "clean" debt increase that was free of unrelated add-ons.

"The creditworthiness of the United States is an essential component of our strength as a nation," Lew wrote. "Protecting that strength is the sole responsibility of Congress, because only Congress can extend the nation's borrowing authority."