(CNN) -- Second seed Venus Williams crashed out of the French Open with a straight sets defeat to Nadia Petrova of Russia in their fourth round clash in Paris on Sunday.
Williams, a runner-up at Roland Garros in 2002 and hoping to meet her sister Serena in the final, was beaten 6-3 6-4 to Petrova, the 19th seed, on Court Philippe Chatrier.
Petrova, who ended the hopes of home hope Aravane Rezai in the previous round, saved two break points at a crucial stage in the first set before converting the chance that came her way to take an early advantage.
Williams broke early in the second set, but lost her own service twice to fall into deep trouble.
The Russian was 5-3 and 30-0 up on Williams's serve when she made two unforced errors, but she converted her first match point with a fine forehand to progress to the quarterfinals.
(CNN) -- Lewis Hamilton and Jenson Button secured a McLaren one-two in a dramatic Turkish Grand Prix on Sunday as they took advantage of a collision between Red Bull pair Mark Webber and Sebastian Vettel.
Polesitter Webber was leading when his German teammate tried to overtake him on lap 41 of 58 and succeeded only in crashing into him and going off.
Webber, who looked set for this third straight victory, had to pit to have a new nose cone, leaving Hamilton, who had been strongly challenging in third, to take the lead from Button, the reigning world champion.
The pair then engaged in their own private duel, with Button briefly heading his fellow Briton, before Hamilton took the lead for the final time to secure his first win of the season.
Webber completed the podium and the third place helps him maintain the lead in the title race, five points clear of Button, with Hamilton moving up to third place, four points further adrift.
(CNN) -- Colombians went to the polls Sunday in a tight presidential race that many didn't expect would be so close just a few months ago.
Voting was proceeding smoothly for the most part, though a government official reported isolated clashes between the military and armed groups in the country's interior. One soldier was killed in one of the skirmishes, Justice and Interior Minister Fabio Valencia said.
The winner of the election will replace two-term President Alvaro Uribe, who has high approval ratings for his tough stand against Marxist guerrillas that have been waging war against the government since the 1960s. Uribe also has been sparring with Venezuelan President Hugo Chavez, who Colombia accuses of supporting the rebels.
Chavez told CNN en Español he will be glad to see Uribe go.
"I think it will refresh all of Colombia. And it will refresh I hope and I think the relationships Colombia, our sister, has with Latin America, with the Caribbean," Chavez said in an interview that will air on the network Tuesday.
(CNN) -- The chief of the Canadian forces in Afghanistan has been relieved of duty following allegations of an inappropriate relationship, the country's military said.
The Canadian military has a strict non-fraternization policy. And Brig. Gen. Daniel Menard's alleged relationship caused the military to "lose confidence" in his ability to command, the National Defence and the Canadian Forces said in a statement late Saturday.
The military said it will not release additional details about the allegations, but that it had launched an investigation.
For now, the military has appointed Col. Simon Hetherington, the current deputy-commander, to lead the 2,800 Canadian soldiers in the country.
On Tuesday, Menard was fined $3,345 -- the stiffest fine ever levied on a Canadian soldier for mishandling a weapon, CNN affiliate CBC said.
Menard was boarding a helicopter at Kandahar Airfield in southern Afghanistan on March 25 when he said his rifle accidentally went off while he was was loading it.
No one was hurt in the incident. But Menard faced a court martial in western Quebec, where he pleaded guilt to accidentally discharging a weapon.
Mexico City, Mexico (CNN) -- A prison warden in the Mexican state of Morelos was abducted as he reported to work Saturday morning and his dismembered body was found later in four locations in the city of Cuernavaca, the government-run Notimex agency reported.
The warden was identified as Luis Navarro Castaneda, director of the Atlacholoaya prison.
Written messages were left with the body remains, Notimex said. The news agency did not report what the messages said.
Navarro's abandoned Toyota truck was found near the prison, Notimex said.
No arrests had been announced as of Sunday morning.
(CNN) -- Chinese Premier Wen Jiabao said Sunday that Northeast Asia -- which includes the Korean Peninsula -- must push for peace and avoid violent clashes in the aftermath of the sinking of a South Korean warship, state news reported.
"We must promote peace and stability in the Northeast Asian region through every effort," Wen said, according to South Korea's Yonhap news agency. "We should be considerate of each other on a grave issue, deal reasonably with a sensitive matter and strengthen political trust".
His comments to reporters came after two days of meetings with South Korean President Lee Myung-bak and Japanese Prime Minister Yukio Hatoyama on the South Korean island of Jeju.
The summit came amid mounting regional tension, but was scheduled before the release of a report accusing North Korea of firing a torpedo that sank the Cheonan warship, killing 46 sailors.
Lee has said that his government planned to bring the issue before the U.N. Security Council. But any attempts to seek penalties against North Korea there would need the cooperation of China -- which has veto power on the council.
North Korea has denied the South Korean report's claims. And China, long North Korea's main international supporter, has steered clear of publicly taking sides on the issue.
Bangkok, Thailand (CNN) -- Thai Prime Minister Abhisit Vejjajiva said the country was calm Sunday morning after the first night without a government-imposed curfew in 10 days, state media said.
In his weekly television address, Abhisit said the state of emergency could be lifted, but did not say when a relaxation or removal of emergency regulations would take place, the Thai News Agency reported.
Officials implemented the state of emergency on April 7 in Bangkok and nearby provinces, when thousands of anti-government protesters had amassed in the capital's central shopping district. They imposed a curfew in Bangkok and 23 provinces May 19.
Violent clashes between the demonstrators and government troops broke out earlier this month, killing at least 50 people and injuring nearly 400, government officials said.