Boston ? Kenya reclaimed the Boston Marathon on Monday, sweeping the first four men’s spots and the top two for the women.

Rodgers Rop held off Christopher Cheboiboch by three seconds to win in 2 hours, 9 minutes, 2 seconds. Margaret Okayo won the women’s race in a course record 2:20:43, pulling away from two-time defending champion and world record-holder Catherine Ndereba in the final mile.

“I just feel proud when I hear that national anthem being played,” Ndereba said after she embraced Okayo. “And if it was not for me, it’s for Margaret.”

Kenyans had won the men’s race for a decade before Lee Bong-ju of South Korea ended the streak last year. But the Kenyans were back in force, taking six of the top seven spots and nine of the top 13.

“The Kenyans are very happy. Last year, I was not happy,” Rop said. “Before running, I said, ‘We have to reclaim our title.’ It’s become a tradition in Kenya to win Boston, so I had to try my level best to win.”

Fred Kiprop outsprinted Mbarak Hussein, the brother of three-time Boston champion Ibrahim Hussein, to finish third, 43 seconds behind the winner. Lee, the defending champion, was the top non-Kenyan again, but he was fifth after falling out of the lead pack by the 19-mile mark.

Keith Dowling, of Reston, Va., finished 15th and was the top American.

Ndereba was running in her first marathon since setting the women’s world record of 2:18:47 last year in Chicago. She lost a sprint with Okayo in the final mile and finished 29 seconds back.

“My goal was to break the course record,” Ndereba said. “And I did it.”

Ethiopia’s Elfenesh Alemu was third, 5:18 behind Okayo. Jill Gaitenby, of Northampton, Mass., was the top U.S. woman for the second consecutive year, finishing 13th.

South Africa’s Ernst Van Dyk won the wheelchair race by almost three minutes in 1:23:19. Edith Hunkeler of Switzerland won the women’s wheelchair race in 1:45:57.

A lead pack of more than 20 men ran together through the midway point before stragglers fell off the pace. The two Kenyans were in the lead alone by the 22-mile mark, and Rop slowly pulled away before Cheboiboch made a desperate sprint down Boylston Street, unable to close the gap.

The winners on the hilly Boston course were almost 3 1/2 minutes behind the world record of 2:05:38 set on a flatter and faster London course Sunday by Khalid Khannouchi.

A forecast of 80-degree weather did not materialize, as the temperatures were 53 degrees at the start, 54 at the midpoint and 56 at the finish. But a low ceiling of clouds grounded helicopters and kept the first 45 minutes of the men’s race and almost all of the women’s race off television.

The annual Patriots Day race the first since the Sept. 11 attacks had an American flair, with nearly 17,000 runners serenaded by national songs before crossing a red, white and blue starting line for the 26.2-mile run to Boston’s Back Bay. A fighter jet flyover was canceled because of the weather.

At the finish, four 45-by-90-foot U.S. flags were unfurled on Boylston Street.

The aftermath of the attacks was also visible in an unprecedented security force, including about 600 police officers who ran in the race. There were no specific threats directed at the marathon, but race organizers followed the trend of other big sporting events by beefing up security.

Bomb-sniffing dogs, hazardous materials teams and radiation detectors were added or increased this year, and the whole crew was in contact with the state’s emergency bunker in Framingham. Runners submitted information for background checks.

Last year, Lee became the first non-Kenyan to win the Boston Marathon since 1990 and the first from South Korea to win here since the Korean War. Feted as a hero in his homeland following last year’s victory, he is planning to get married in less than a week.