Tens of thousands of participants from 160 countries have gathered to participate in the 40th Paris marathon. The city is on high alert following recent terror strikes in Brussels and two big attacks in France last year.
The city of Paris tweeted the start of the run from its official account.
About 57,000 runners from 160 countries registered for the 42.19-kilometer (26.7 miles) race, beginning at the Champs-Elysees and ending at the Bois de Vincennes in Paris' east.
Tens of thousands of spectators were also expected to line the streets. Special festivities were planned at the 40-kilometer mark, in honor of the original race, run in 1976.
Last year's winners, Ethiopian Meseret Mengistu in the women's category and Kenyan Mark Korir in the men's category, were taking part in the run and would be the first runners in the marathon's history to defend their titles.
Life goes on
Despite the recent terror attacks in Brussels and strikes on Paris last year, runners seemed to be keen to join the marathon.
"There is absolutely no psychosis … After the events of November 13, we received a lot of emails asking if the marathon was going ahead. Notably emails from Americans and foreigners. This phenomenon was not repeated after the dramatic events of recent weeks," marathon Director Edouard Cassignol said.
"We also plan spotters, people trained to detect any abnormal behavior and finally we briefed our nearly 3,000 volunteers on being vigilant on D-day," Cassignol added.
The Prefecture of Police said in Paris that several hundred police officers were deployed for the run and special teams would be present at the start and finish zones to protect participants.
"They will carry out checks in support of an important filtering system set up by the organizers. There will be systematic pat downs of the public with bags checked. Similarly, patrols will be mobilized to secure the entire route taken by the runners," police said in a statement.
On average, around 10,000 runners registered for the marathon fail to turn up every year. Official figures for this year have not yet been released, but it remains to be seen if recent terror attacks have had any impact.
Paris has been on high alert after terrorists struck Belgium's capital Brussels last month, killing 32 people. The French capital itself has been the target of several strikes. Last November, 130 people were killed in coordinated strikes, including at the Stade de France football stadium and the Bataclan concert hall. In January 2015, 17 people were killed at a Jewish supermarket and the office of satirical magazine Charlie Hebdo.
mg,blc/jlw (AFP, AP)