The Treasury Department, adding urgency to President Barack Obama’s call for action on the federal debt ceiling, said Monday the government was on track to hit its borrowing limit as early as the middle of February.

Unless Congress raises the government’s $16.4 trillion debt limit, “Treasury would be left to operate solely with the cash we have on hand on any given day” and would likely have to delay payments on everything from bond obligations to income tax refunds, Social Security benefits and military salaries, Treasury Secretary Timothy F. Geithner said in a letter to House Speaker John A. Boehner, R-Ohio.

In the letter, Geithner narrowed the period when the steps Treasury has been taking to stave off the day of reckoning to “between mid-February and early March.”

Geithner had said in a letter to Congress on Dec. 26, 2012, that the government was due to hit its borrowing limit in days but that the department would take “extraordinary measures” that could keep operations running normally for about two months.

And Geithner reiterated that the department could not prioritize payments, as some Republican lawmakers have suggested as a way to forestall default on obligations and keep some benefits moving.

“The U.S. government makes approximately 80 million separate payments per month,” Geithner wrote in the letter to Boehner.

He listed a litany of accounts that would be endangered, including payments for Social Security, Medicare, Medicaid, veterans’ benefits, military salaries, law enforcement, disaster relief and income tax refunds, as well as the bond obligations that would roil markets.

“If Congress does not act to extend borrowing authority, all of these payments would be at risk,” Geithner wrote. “This would impose severe economic hardship on millions of individuals and businesses across the country.”