WASHINGTON, United States -- The leader of the Democratic-controlled US House of Representatives vowed Thursday to avert a looming government shutdown as federal funds run out, despite a pledge by opposition Republicans to block the move.

Lawmakers have until September 30 to green-light a package to fund the government ahead of the stoppage, which typically leads to hundreds of thousands of workers being sent home while parks, museums and other federal properties and services are closed.

The House passed a ''continuing resolution'' (CR) Tuesday which would keep federal agencies open until December 3 -- a move supported by Republicans.

But Democratic leaders also attached a debt ceiling suspension following warnings that the Treasury Department will be unable to obtain new loans some time in October.

The debt ceiling is the amount above which the country cannot issue new loans to fund government agencies and make loan repayments.

Republicans usually support raising the debt limit but have vowed to block any stopgap funding bill that extends the Treasury Department's borrowing authority this time around.

''Whatever it is, we will have a CR that passes both houses by September 30,'' Speaker Nancy Pelosi told a news conference -- without giving details on the plan to break the deadlock.

Economists estimate that failure to extend the debt limit would erase six million jobs and wipe out $15 trillion of household wealth, tanking the economy and threatening a global meltdown.

Republicans are refusing to help solve the impasse in protest at President Joe Biden's plans for an ''irresponsible'' $3.5 trillion public works package on top of a $1.2 trillion infrastructure spending bill that already passed the Senate with cross-party support.

Without Republican backing, however, it is not clear how the CR will get the 60 votes it needs to advance in the Senate, where the 100 seats are evenly divided between the two parties.

'One day at a time'

House Minority Leader Kevin McCarthy echoed the Republican position, saying Democrats can avoid a shutdown and debt crisis on their own using a process called ''reconciliation,'' which allows certain budget-related legislation to pass the Senate with a simple majority rather than 60 votes.

Then in the event of a 50-50 vote, Democratic Vice President Kamala Harris would break the tie.

''The Democrats control the House, the Senate and the White House.... If they want to raise and spend another $5 trillion, that's what they need to do,'' McCarthy told reporters.

The coming few weeks are among the most critical of Biden's tenure has he bids to demonstrate his dealmaking chops with the complicated passage of two giant spending bills.

Democrats are preparing for a frenetic stretch of late nights as they race to finalize their $3.5 trillion social spending plan, dubbed ''Build Back Better.''

And Pelosi has promised House moderates a September 27 vote on the $1.2 trillion Senate-passed infrastructure bill to rebuild the nation's roads and bridges.

House progressives have repeatedly warned that they won't green-light infrastructure without Build Back Better.

But moderates -- some of whom are nervous about the high ticket price -- may not vote for the bigger bill without infrastructure crossing the line first.

Defeat on either front would be a disaster for Biden and dim Democrats' hopes of hanging on to the House and possibly the Senate in next year's midterms.

''We take it one day at a time. But I am confident we will pass both bills,'' Pelosi said.