Questions are being asked about how a potentially lethal security breach could have occurred during US President George W Bush's trip to Georgia on Tuesday.
Mr Bush's movements during foreign trips are choreographed down to the minutest detail by the US Secret Service and other agencies. Yet, according to security officials, someone was still able to place a hand grenade within 50m of the president and his Georgian counterpart Mikhail Saakashvili.
Mr Bush was protected by a giant bullet-proof screen
The two had just finished addressing a huge rally in Tbilisi's Freedom Square when the device was found. Georgian officials say the hand grenade was inactive and therefore did not pose any danger to either of the presidents.
However, the incident highlights the difficulties in protecting the US president when he is not on his home territory and the US Secret Service says it is investigating the incident.
After the assassination of President William McKinley in 1901, Congress directed the US Secret Service (USSS) to protect the president. Such protection remains the agency's primary mission.
Planning for a trip
From the moment a trip is discussed in the White House, secret service agents begin looking at the various security scenarios. Plans are worked and re-worked, taking in changing intelligence information.
Advance teams of agents are then dispatched to the various destinations on the president's itinerary.
US snipers were visible on rooftops and American agents manned security gates
When the president does finally turn up, he does so with a small air force, a massive entourage and a motorcade of armour-plated vehicles. These include the president's bullet-proof limo, a military ambulance and a communications van packed with state-of-the art devices.
Around 250 heavily-armed secret service agents, dozens of advisers and teams of sniffer dogs escort Mr Bush on most foreign trips. White House cooks join government political aides.
"When the president travels, the White House travels with him from the cars he drives, the water he drinks, the gasoline he uses, the food he eats," says John Barletta, former secret service agent for Ronald Reagan, who organised overseas visits.
Speaking to the BBC, he said the Georgia incident is the kind of incident that agents have "nightmares over".
But he said the fact that the device did not detonate and harm the president highlighted just how intense the security around the president was.
Georgian National Security Council Secretary Gela Bezhuashvili said there was no danger to the president from the device found near the stage.
As he delivered his speech to 120,000 cheering people, President Bush was protected by a huge transparent bullet-proof screen.
Soldiers were posted on rooftops surrounding the large open area. Secret Service agents, who had spent weeks in the Georgian capital making preparations, scrutinised the dense crowd during the president's speech. US snipers were visible on rooftops and American agents manned security gates.
According to Russian air force officials, the US had been flying additional U-2 reconnaissance missions over the Caucasus region in preparation for Mr Bush's visit to Moscow and to Georgia.
Mr Barletta said providing security for presidents was an increasing challenge.
"Now you are looking for other things - for terrorist activities, someone could put a missile in there, now you are looking for aircraft that could explode into a crowd," he said.
"The secret services assigned to protect the president have widened their circle drastically."
He said that the way agents operated had changed enormously since he was working.
"Intelligence gets better, electronics get better - the whole thing keeps advancing weekly," he said.
Mr Bush's appearance at a public gathering in Georgia broke the mould of foreign trips. Usually, the president is cocooned at state dinners and other official functions.
Last year, his visit to Chile sparked a diplomatic incident when a state banquet had to be cancelled after Chilean officials objected to the US security arrangements.
The US Secret Service insisted on checking all guests, including the president of the Chilean Senate and the heads of each branch of the Chilean armed forces and their wives for weapons, before allowing them to dine near Mr Bush at the presidential palace.
The weak link in US security, however, appears to be when the president appears in public.
"If we had our way, the secret service would put the president in a cement thing and no one would get to see or hear him," says Mr Baretta. He concedes, however, that the president needs to be seen by the people.
US security agents may now, however, caution the president against appearing at such a public event in the near future.