Police arrested this man after he tossed a plastic flip-flop, which hit a building. (CBC)

Four people were arrested in downtown Calgary on Tuesday during a protest outside the building where former U.S. president George W. Bush was making his first official speech since leaving office.

Two men were charged with obstructing a peace officer and resisting arrest. Another man was charged with breaching the peace, while the fourth was issued a ticket for violating a public behaviour bylaw, said Duty Insp. Rob Williams of Calgary police.

Bush addressed an invitation-only crowd of about 1,500 at the Telus Convention Centre in his first speech since leaving office. Tickets were reported to cost $400 per person. Media were not allowed inside.

About 200 protesters crowded around the entrance of the convention centre in the morning, heckling ticket holders and chanting "go home."

"I just couldn't pass up the opportunity to publicly voice my displeasure with the American foreign policy" under Bush, said Jeff Gaillus, who was carrying a rod with a shoe at the end of it. "I'm not sure what he has to tell us to shed wisdom on the future of the planet."

'The criminal is inside'

One protester, who told CBC News he was "making a statement," tossed a plastic flip-flop sandal, which hit a building. Police handcuffed him and put him inside a police van, saying he was going to be ticketed.

"What are you doing arresting that man? The criminal is inside," shouted a protester while others chanted, "Let him go."

Police arrest a man in a Calgary intersection. (CBC)

Several people used shoes as props during the protest, a nod to an incident in December 2008 in which an Iraqi journalist hurled two shoes at Bush during a news conference in Baghdad. Bush ducked, and the shoes never made contact with their target. Nevertheless, the journalist, Muntazer al-Zaidi, was sentenced last week to three years in prison for assaulting a foreign head of state during an official visit.

A lineup of people holding tickets to the event — the majority wearing business suits — stretched about two city blocks Tuesday morning, but they were inside the building by 1 p.m. MT, a delay of half an hour.

Security was tight as all guests were searched before entering the hall. Calgary police said they assigned a total of 79 officers, including traffic units, to the event.

Among those waiting to hear Bush speak were Senator Pamela Wallin, former Alberta energy minister Murray Smith, CBC hockey broadcaster Kelly Hrudey, former Alberta premier Ralph Klein and Calgary aldermen John Mar and Ric McIver.

A person dressed as a Guantanamo Bay prisoner tried to use a jury-rigged cannon device to fire shoes out onto Stephen Avenue Mall, but police stepped in. (Andree Lau/CBC)

"You might not agree with eight years of the policies of Bush… but if he is here, might as well hear what he has to say," said Paul Dhillon, who was waiting in line to go into the event.

After the almost one-hour speech and question-and-answer session, attendees said Bush was candid and warmed the crowd with self-deprecating humour, joking that Calgary was one of the few places that would have him.

"This is my maiden voyage. My first speech since I was the president of the United States, and I couldn't think of a better place to give it than Calgary, Canada," the 43rd U.S. president said to largely friendly audience.

Bush defended his reasons for invading Iraq and Afghanistan as the appropriate approach to spreading democracy.

A lineup of people holding tickets to the event stretched about two city blocks Tuesday morning. (Andree Lau/CBC)

"He said if we were in his boots in 9/11, a short time after he got in, there was a big demand to do something, and he had to react and he reacted," said George Fink, CEO of Bonterra Oil and Gas.

Bush also touched on the current economic slump, warning against too much government intervention.

"It's the risk takers, not the government, that is going to pull us out of this recession," he told the crowd. "I'm a free trader to the core."

Attendee John Owen said the address was interesting. "You get the sense that he genuinely believes in what he's saying… whether or not you believe or agree with him."

Shoes thrown at Bush billboard

Critics of Bush's visit held small demonstrations leading up to his speech, calling for his arrest as a war criminal for his alleged sanctioning of torture at U.S. military prisons in Iraq and Guantanamo Bay, Cuba.

Protesters threw shoes at a billboard image of George W. Bush outside the Telus Convention Centre, where the former U.S. president was speaking. (Andree Lau/CBC)

The protesters included a person dressed as a Guantanamo Bay prisoner who tried to use a jury-rigged cannon device to fire shoes in front of the convention centre, but police moved her further away down Stephen Avenue Mall.

Another protester, Doug Beck, who was wearing work boots around his neck and carrying several other pairs with his hands, called it "performance art."

"Four hundred dollars a plate? They've got to think of something better [to do] with that money," Beck said, pointing to the lineup.

Protesters made speeches denouncing Bush and his decision to invade Iraq and ended the rally by hurling shoes at a billboard with a poster of the former president's face.

"We don't agree with his actions," said Heather Hendrie, who attended the protests.

Bush was scheduled to speak "on eight momentous years in the Oval Office" and "the challenges facing the world in the 21st century," according to promotional materials for the event.

Organizers Andy McCreath and Christian Darbyshire reportedly paid former U.S. president Bill Clinton $150,000 for a March 2006 speech in Edmonton and have hired Lance Armstrong and Colin Powell for other high-profile speaking engagements in the past.

With files from Andree Lau and the Canadian Press