VANCOUVER, British Columbia — A couple from British Columbia who styled themselves as the sole members of “al-Qaida Canada” built pressure-cooker bombs and planted them on the grounds of the provincial legislature hours before Canada Day festivities, a prosecutor said Monday.

John Nuttall and Amanda Korody have pleaded not guilty to charges of conspiring to commit murder, conspiring to place explosives on behalf of a terrorist group, facilitating terrorist activity and possessing explosives on behalf of a terrorist group.

The pair was arrested in July 2013 after an undercover operation that began months earlier, when a Royal Canadian Mounted Police officer met Nuttall at a gas station near Vancouver.

The bombs did not explode because undercover RCMP officers had ensured they were inert. But Nuttall and Korody intended to kill and maim an untold number of victims on the morning of July 1, 2013, prosecutor Peter Eccles told the jury at the start of the trial.

Nuttall, who wore a dark suit jacket, smiled during the hearing and occasionally turned to look at his mother in the gallery. Korody wore a green shawl and mostly looked down as the prosecution outlined the allegations.

The undercover officer who met with Nuttall posed as an Arabic businessman, Eccles said.

Nuttall allegedly told the officer that he was a convert to Islam and that he considered himself part of the mujahedeen. He also expressed his support for the Boston Marathon bombers, and he was particularly interested in the type of bomb they used.