US President Barack Obama's first public act in office yesterday was to institute new limits on lobbyists in his White House and to freeze the salaries of high-paid aides, in a nod to the country's economic turmoil.

Announcing the moves while attending a ceremony to swear in his staff, Obama said the steps "represent a clean break from business as usual".

The pay freeze would hold salaries at their current levels for the roughly 100 White House employees who make over $100,000 (Rs 49 lakh) a year. "Families are tightening their belts, and so should Washington," said the new president, taking office amid startlingly bad economic times that many fear will grow worse.

Those affected by the freeze include the high-profile jobs of White House chief of staff, national security adviser and press secretary.