LONDON: Three British Muslims were convicted Monday of plotting to murder thousands by downing at least seven airliners bound for the U.S. and Canada in what was intended as the largest terrorist attack since Sept. 11.

A jury at a London court found Abdulla Ahmed Ali, 28, Assad Sarwar, 29, and Tanvir Hussain, 28, guilty of conspiracy to murder by detonating explosives on aircraft while they were in-flight.

Four other alleged conspirators — whom the prosecution said were to have smuggled liquid explosives onboard jetliners disguised as soft drinks — were acquitted of conspiring to blow up planes. The jury could not reach a verdict on an eighth man.

British and U.S. security officials said the plan — unlike many recent homegrown European terrorist plots — was directly linked to al-Qaida and guided by senior Islamic militants in Pakistan, who hoped to mount a spectacular strike on the West.

The officials said British plotters were likely just days away from mounting their suicide attacks when police rounded up 25 people in dawn raids in August 2006.

Their arrests led to travel chaos as hundreds of jetliners were grounded across Europe. Discovery of the plot also triggered changes to airport security, including new restrictions on the amount of liquids and gels passengers can take onto flights.

Prosecutors said suspects had identified seven specific flights from London's Heathrow airport to New York, Washington, Chicago, San Francisco, Toronto and Montreal, as their targets.

British authorities estimate that, if successful, around 2,000 passengers would have died. If bombs were detonated over U.S. and Canadian cities, hundreds more would have been killed on the ground.

Plotters planned to assemble bombs in airplane toilets using hydrogen peroxide-based explosives injected into soda bottles.

"They were to be detonated in-flight by suicide bombers," including several of the accused, prosecutor Peter Wright said.

Tests by scientists who replicated the bombs in a laboratory showed the devices could produce powerful explosions, though there is no evidence that the terrorist cell had perfected the technique.

Wright told the trial that the group's suicide attacks were planned by "men with the cold-eyed certainty of the fanatic" and intended as "a violent and deadly statement of intent that would have a truly global impact."

He said the plot would have caused "a civilian death toll from terrorism on an almost unprecedented scale."

All eight defendants had denied most charges against them, claiming they were planning a stunt — and not a terrorist attack — to expose failings in Western foreign policy.

Prosecutors were unable to produce evidence that the men had produced a single viable bomb. The trial was the second to take place in a case which has frustrated prosecutors.

Last year, Ali, Sarwar and Hussain were convicted of conspiracy to murder, but the jury could not reach a verdict on whether they specifically targeted aircraft. The jury at that trial failed to reach verdicts against other four defendants.

Jurors on Monday cleared Donald Stewart-Whyte, 23, of all charges. They found Umar Islam, 31, guilty of a charge of conspiracy to murder, but could not decide if he was involved in targeting aircraft.

They found three other men: Ibrahim Savant, 28, Arafat Waheed Khan, 28 and Waheed Zaman, 25, not guilty of planning to blow up airliners, but could not reach verdicts on whether the three men were guilty of conspiracy to murder.

Each defendant, except Stewart-Whyte, had pleaded guilty to a lesser charge of conspiracy to cause a public nuisance.

Prosecutor Adina Ezekiel said authorities will announce if they will seek a third retrial.