Mohammad Momin Khawaja (second from left) is shown in a courtroom in this artist's sketch, as his trial begins Monday in Ottawa. Khawaja, arrested in 2004, is accused of involvement in plans to bomb sites in England in early 2004. He has pleaded not guilty. (Tammy Hoy/Canadian Press)The first man ever charged under Canada's Anti-terrorism Act sent e-mails while at work inside the Foreign Affairs Department about detonators to be used in planned bombed attacks in Britain, prosecutors alleged Monday at the start of his trial.

Downtown Ottawa was under tight security Monday morning for the first day of the high-profile trial of Mohammad Momin Khawaja, a computer software developer who was working for Foreign Affairs when he was arrested in 2004.

Tactical squads and bomb-sniffing dogs surrounded the federal courthouse on Elgin Street ahead of the trial. Concrete barriers blocked vehicle access to the front doors, and those attending were required to pass through a metal detector.

During his lengthy opening statement, prosecutor David McKercher said Khawaja was "directly involved" with the British bomb plot and met with members of the cell in 2003 and 2004.

A tactical police officer with an automatic weapon waits at the entrance of an Ottawa courthouse ahead of Mohammad Momin Khawaja's arrival on Monday. (Tom Hanson/Canadian Press)

He alleged Khawaja used his credentials to get into Britain. In e-mails, he considered using a courier hired by Foreign Affairs to send the remote-control detonators — a device he dubbed "hi-fi digimonster" — to London, McKercher alleged.

Khawaja entered a plea of not guilty Monday. Dressed in a grey suit, with his long hair tied behind his head in two ponytails, the 29-year-old accused took notes and appeared to be following the morning's proceedings attentively, the CBC's Rosemary Barton reported from outside the courtroom.

The case has garnered international attention. Khawaja faces seven charges, and is accused of involvement in plans to bomb sites in England in early 2004.

"The Americans and the Brits are watching this case closely as well, as a sign to see whether Canada takes terrorism very seriously," Barton said.

Mohamed Junaid Babar, shown in an artist's sketch, testified Monday. (Tammy Hoy/Canadian Press)

FBI informant to testify

Police raided Khawaja's family home in the capital in March 2004 as part of a British and Canadian investigation.

Five British men charged in the case were convicted in 2007 and sentenced to life in prison.

Mohammed Junaid Babar, the prosecution's main witness and an FBI informant, began testifying on Monday.

He pleaded guilty in a New York court in 2004 to setting up terrorist training camps in Pakistan and was the star witness in the trials of the five men in the British cell.

Babar began his testimony by admitting to being part of a plan to assassinate Pakistani President Gen. Pervez Musharraf.

That plan, however, fell apart when a member of their group was captured, Babar said. As a result, he ended up burying AK-47s, ammunition and hand grenades that had been intended for use in the assassination.

As he began his testimony, Babar did not link Khawaja to the terrorist group.

Software designer denies charges

Khawaja, who has spent the past four years behind bars, is accused of building remote-control triggering devices for a bomb-making cell east of London plotting to attack nightclubs and shopping centres.

Khawaja denies charges he was a co-conspirator in the al-Qaeda-inspired British cell.

Michel Juneau-Katsuya, a former officer with the Canadian Security Intelligence Service, said fears that the Ottawa courthouse could be a tempting target will likely see security levels rise to an unprecedented level.

"This is a fantastic opportunity, knowing that international and national media will be paying close attention," Juneau-Katsuya told CBC News on Monday. "If they were to commit an attack there, that would sort of be a fantastic coup."

The trial is expected to run until October or November. Superior Court Justice Douglas Rutherford will preside over the trial, by judge alone.

If convicted, Khawaja could face a maximum sentence of life in prison.