President Joe Biden and Republicans in Congress have resumed crunch talks aimed at averting a damaging US debt default, which Treasury officials recently warned could come as early as June 1. Biden has maintained that default would have "catastrophic" consequences, and is urging Republicans to agree to a "clean" increase to US borrowing limits -- known as the debt ceiling -- before the deadline is reached. Republicans have pushed back, insisting they want an agreement from Democrats to commit to less spending in future in order for their support to extend the nation's borrowing authority.