Obama called the rules, which were created by executive order, tighter "than under any other administration in history."

"The new rules on lobbying alone, no matter how tough, are not enough to fix a broken system in Washington," he said. "That's why I'm also setting rules that govern not just lobbyists but all those who have been selected to serve in my administration."

Under the rules, White House aides must wait two years after leaving the administration before trying to influence former friends or colleagues in the White House. Those already hired cannot work on issues on which they previously lobbied, nor can they try to influence federal agencies they once lobbied.

Every full-time political appointee must sign an ethics pledge agreeing not to accept gifts of any size from registered lobbyists, lobbying firms or lobbyist employers. Some traditional exceptions from the gift-giving prohibitions remain, but some have been removed. For example, there is no longer an exception for "widely-attended gatherings."

Obama is also requiring that all staffers attend an ethics briefing like one the new president recently attended.

Democracy 21 President Fred Wertheimer praised the new rules as "ground breaking." They are, he said, "a major step in setting a new tone and attitude for Washington that challenges the lobbyist, special-interest culture that pervades the nation's Capitol."

"We strongly praise President Obama for issuing this landmark Executive Order on his first day in office and demonstrating by his actions that he takes very seriously the importance of protecting the integrity of the government he leads, and, in so doing, the interests of the American people," Wertheimer said.

But Dave Wenhold of the American League of Lobbyists called the new rules "seriously flawed."  

"This executive order will do more harm than good and, quite frankly, it hurts the country by keeping experts out of the system," Wenhold said.