In London,no running away

However,British sports minister Hugh Robertson said the London version,watched by an estimated 500,000 spectators and run through some of the citys most recognizable landmarks,should be staged as planned to show we wont be cowered by this sort of behavior.

The best way for us to react is to push ahead with the marathon on Sunday,to get people on the streets and to celebrate it as we always do in London, said Robertson,who hailed Britains security forces as the best anywhere in the world.

These are balance of judgments but we are absolutely confident here that we can keep the event safe and secure. I think this is one of those incidents where the best way to show solidarity with Boston is to continue and send a very clear message to those responsible.

Security is being scrutinized after the events in Boston,where two bombs exploded near the finish of the marathon,but there have been no high-profile withdrawals and Prince Harry the patron of the London Marathon Charitable Trust 8211; will attend the race and make the presentations to the winners.

The London Marathon fully expects at this stage 8230; to go ahead as planned on Sunday although we are continuing to review security with the Metropolitan Police in the coming days, Nick Bitel,chief executive of the London Marathon,said on Tuesday in an interview on the race website.

The London Marathon will be in touch with the runners through their email and they will hear from us on a daily basis in that way. We will try to keep updating our runners throughout this period. Bitel told the BBC: When you have an event of any nature a marathon,parade 8211; its only as safe as the city itself. If its not held in a stadium,you cant do a lockdown like you may do in a building.

Mo Farah to participate

Mo Farah,Britains double Olympic long-distance champion,will be running a half-marathon while the three medallists from the mens marathon at the London Games are also among the 37,500 entries.

Sundays race is one of six in the world marathon series along with Tokyo,Boston,Berlin,Chicago and New York.

Theres rather intense activity going on to ensure the race is safe and is carried off with the usual aplomb, said Ed Warner,chairman of UK Athletics. The decision at the moment is to go ahead with the race and Im sure it is the right decision. They will cope very well with the increased demands placed on them.

Belgrade is among other cities staging marathons this weekend,with organizer Dejan Nikolic expressing confidence that the race will be safe and a beautiful running festival.

We will do our best so that this year the security level is even higher, Nikolic said. In 2005,suicide attacks on the public transport system in the British capital killed 52 people.

London and mainland Britain also face a moderate threat from Northern Ireland-related terrorism,according to the government,and a massive security operation was put in place last summer to protect the successful London Olympics.

This years Boat Race between English universities Oxford and Cambridge went ahead amid tightened security after a protester jumped into the River Thames last year and narrowly avoided being hit by the oars of the two crews. Royal Marines were stationed along the length of the 4 1/4-mile nearly 7-kilometer course.

Focus shifts to Sochi

From London to Sochi to Rio de Janeiro,the deadly bomb attacks on the Boston Marathon raised new concerns Tuesday over safety at major sports events around the world,including the Olympics and World Cup.

We are very,very concerned, senior IOC member Gerhard Heiberg of Norway said on Tuesday. Security is priority No. 1,no question about it.

The focus now falls on Sochi,a Black Sea resort that will host Russias first Winter Olympics next February. Security was already a concern because of Sochis proximity to an Islamic insurgency that spread across southern Russia after separatist wars in Chechnya.

Naturally,were beefing up security measures, Russian Sports Minister Vitaly Mutko said in remarks carried by the R-Sport news agency.

IOC vice president Thomas Bach,who was on his way to Sochi on Tuesday for an international journalists conference,said the attacks in Boston reinforced the IOCs policy that safety is paramount for any Olympics.

Im sure that this malicious attack will lead the public authorities to have another look at all security measures, Bach said on Tuesday.

While it is too early to draw any final conclusions,we have full confidence in the Russian authorities.

Blood on the field

Sept. 5,1972: Eight members of the Palestine Liberation Organisation PLO splinter group Black September raided the Israeli teams quarters in the Olympic village in Munich,killing a weightlifter and a wrestling coach almost immediately. They took nine athletes and officials hostage and demanded the release of more than 200 prisoners held in Israel. Later,at Munichs military airport,from where the guerrillas were hoping to leave Germany,police opened fire and a gunfight erupted. All the hostages were killed and five of the gunmen and a policeman also died.

July 1996: A powerful nail bomb exploded in Centennial Olympic Park on July 27 during the Atlanta Olympics. One person died and more than 100 were hurt. Eric Rudolph,who was sentenced to three life terms without parole in 2005 for Atlanta and other bombings,said the Olympic attack was designed to confound,anger and embarrass the Washington government in the eyes of the world for its abominable sanctioning of abortion on demand.

June 1998: An Algerian cell funded by Osama bin Laden planned to attack the World Cup finals in France,targeting the US Embassy in Paris and the US soccer team. The cell also planned a pitch assault on the England team during their group match against Tunisia in Marseilles. Individuals were arrested by French intelligence,foiling the plot.

2002: Khalid Sheikh Mohammed,Al Qaedas operational leader who was arrested in 2003,revealed that the group had intended to carry out attacks in Japan during the soccer World Cup jointly hosted with South Korea. The attacks did not go ahead as the group failed to establish a network there.

May 2002: A car bomb exploded in the Pakistani city of Karachi near the hotel where the New Zealand cricket team were staying,killing 13 people including 11 French navy experts. New Zealand called off the tour after the attack.

May 26,2006: Gunmen killed the coach of Iraqs national tennis team and two of his players in Baghdad,days after militants issued a warning forbidding the wearing of shorts.

May 17,2006: Some 15 athletes and officials from a taekwondo squad were kidnapped from a highway in western Iraq as they travelled to a training course in Jordan. The decomposed bodies of at least 13 of the squad were found in the desert in June 2007.

July 16,2006: Up to 50 gunmen seized some 30 Iraqi sports officials,including the national Olympic chief Ahmed al-Hadjiya,and their bodyguards,in a brazen daytime raid on a central Baghdad hall. They are still missing.

July 31,2006 : Two suitcases filled with explosives were placed on trains near Hamm and Koblenz and would have killed hundreds during the soccer World Cup in Germany. The detonators were faulty and did not ignite the explosives.

March 3,2009: Gunmen attacked a bus carrying Sri Lankas cricket team outside a Lahore stadium in Pakistan,killing seven people,including six policemen and a driver. Six of the cricketers and a British coach were wounded.

Jan. 8,2010: A Togo soccer team bus,travelling from the Republic of Congo to the African Nations Cup in Angola,had just entered Cabinda province when it came under heavy gunfire from separatists. Team media officer Stanislas Ocloo and assistant coach Amalete Abalo were killed.