WASHINGTON (CNN) -- Sen. John McCain, R-Arizona, who had advocated sending as many as 35,000 troops in order to Iraq to make a so-called "surge" successful, said Wednesday he is satisfied with President Bush's decision to send in just over 21,000.

"I think so," McCain said when asked if it was enough. "Because of the number of brigades."

Last week McCain, a key supporter of increasing the number of troops in Iraq, said his primary concern was that President Bush wouldn't send in enough troops.

"I cannot support an insufficient injection of troops," he said at the time. McCain said the experts he consulted said four brigades needed to be sent to Baghdad, two to Al Anbar province, and one to Kuwait ready to move in as necessary. A brigade can consist of 3500 to 5000 troops.

The president's plan reportedly calls for five Army brigades to be sent to Baghdad and 4000 Marines to Al Anbar.

"I think it meets our criteria," McCain said.