OTTAWA - Federal prosecutors are trying to shift their case against Momin Khawaja because they can't tie him conclusively to the British bomb plot in which he was initially charged, says the defence lawyer for the Ottawa software developer.

"It's extremely unfair," Lawrence Greenspon contended at Khawaja's trial Wednesday.

He told Justice Douglas Rutherford, who is hearing the case without a jury, that prosecutors want "not only to change horses but go to a completely different animal" in the middle of the case.

Greenspon is asking Rutherford to quash terrorism charges against his client on grounds that the Crown hasn't produced sufficient evidence of his involvement in a plan to bomb a nightclub, shopping centre and electric and gas facilities in Britain.

The defence lawyer has admitted that Khawaja took weapons training at a camp in Pakistan in 2003, and that he developed a remote-control device dubbed the Hi-Fi Digimonster that could be used to detonate bombs.

But he insists Khawaja's only aim was to join Islamic insurgents fighting western troops -- including Canadians -- in Afghanistan and to use the Digimonster to trigger homemade bombs there.

Evidence gathered by the British security service MI-5 has shown Khawaja visited Omar Khyam, the leader of the British bomb plot, in 2004 and discussed remote-control technology with him.

But Greenspon pointed out that the same bugged conversations were filled with musings by Khawaja about travelling back to Pakistan and eventually to the front lines in Afghanistan.

The only discussion of targets in the U.K. came in conversations between Khyam and his fellow British conspirators -- conversations for which Khawaja wasn't present.

"It's crystal clear," said Greenspon, "that what was discussed in Momin Khawaja's presence had everything to do with going to Afghanistan to fight (and) nothing to do with bombs in downtown London."

He maintained the British conspirators deliberately kept Khawaja in the dark and didn't tell him of their plans to attack domestic targets.

Prosecutors have maintained from the start of the case that Khawaja was a knowing and willing participant in the U.K. plot.

They have yet to respond in detail to Greenspon's assertion that his real target was Afghanistan. But Bill Boutzouvis, one of the Crown attorneys handling the case, dropped a hint of their possible strategy on that point earlier in the trial.

He argued that the core of the case against Khawaja is that he participated in "violent jihad," no matter where his activities took place or what his intended targets were.

Greenspon contends it would be unjust to shift the focus away from the original allegations involving the London plot. Such a switch, he said, would mean that "they charged A and they went on to prove B."

Outside the courtroom, Greenspon acknowledged that, if Khawaja had carried through on his hope to fight and plant bombs in Afghanistan, the victims could have included Canadian soldiers.

"It certainly saddens me, and I'm sure (it does) all Canadians," he said. But he insisted it would be a "perversion" of Canadian law to define such activity as terrorism.

"When we talk about terrorism, we're not talking about people going to fight in a combat theatre against other soldiers."

Khawaja faces seven charges under the Anti-Terrorism Act, including a key allegation that he built the so-called Digimonster.

He's also accused of financing and facilitating terrorism, participating in terrorist training and meetings, and making a house owned by his family in Pakistan available for terrorist use.

Five of his alleged co-conspirators were convicted last year in Britain but Khawaja has pleaded not guilty to all the charges facing him in Canada.

The trial has been adjourned until next Tuesday, when prosecutors will present their counter-arguments to Greenspon's latest contentions.