WASHINGTON - US President George W. Bush took back presidential power after undergoing a routine colonoscopy Saturday.

In this photo released by The White House, US President George W. Bush(R) and Chief of Staff Josh Bolten walk with the President's dog, Barney at Camp David, Maryland. Bush had five polyps removed during a "routine" colon cancer check on Saturday but the White House said there was no cause for concern and that he had resumed power after a brief handover to Vice President Dick Cheney. [Agencies]

The White House made the announcement more than two hours after Bush temporarily ceded power to Vice President Dick Cheney for the procedure at 7:16 a.m.

In a letter sent to both Senate and House leaders, Bush reclaimed his presidential power at 9:21 a.m.

Cheney served as acting president while Bush was under anesthesia during the colon screening.

The colonoscopy was conducted at the presidential retreat of Camp David, Maryland, while Cheney was at his home in St Michael's, Maryland, 50 km east of Washington.

The colon screening lasted about 31 minutes and five small polyps were removed.

"None of the polyps appeared worrisome," White House spokesman Scott Stanzel said, adding that Bush is "in good humor and will resume his normal activities at Camp David."

After the colonoscopy, Bush had breakfast with some White House aides.

It was the second time that Bush has ceded power to Cheney due to a colonoscopy.

On June 29, 2002, Bush handed over presidential powers to Cheney for more than two hours during a routine colon screening.

Although the results were good, doctors advised him to undergo another colonoscopy after five years.

Bush invoked Section 3 of the 25th Amendment to the US Constitution to make the temporary power transfer.

The amendment was adopted in 1967 as a means of dealing with presidential disability and succession.

Bush, 61, is the second president to invoke the presidential disability clause.

Ronald Reagan was the first.

In July 1985, Reagan underwent colon cancer surgery and ceded power to his deputy, the elder Bush.

The White House said no symptoms of cancer have been found in Bush, who is a routine exerciser.

In 1998 and 1999, two polyps were discovered during medical checks when Bush was governor of Texas.

Since then he has been undergoing regular examinations.

For ordinary people, a colonoscopy to screen for colon cancer is recommended every 10 years.

But for a "higher-risk" individual, or if a colonoscopy detects precancerous polyps, follow-up checks will usually be conducted every three or five years.