A jury that convicted four men of plotting to bomb London's public transport system on July 21, 2005, was dismissed Tuesday after failing to reach a verdict against two other defendants.

Judge Adrian Fulford told the jury of nine women and three men on Monday that he would accept 10-2 majority verdicts on Manfo Kwaku Asiedu, 34, and Adel Yahya, 24. He dismissed the jury after less than two hours of deliberations on Tuesday.

Fulford gave prosecutors until Wednesday morning to say whether they would seek a retrial of Asiedu and Yahya.

Authorities believe the failed attacks on three subway trains and a double-decker bus was a deliberate echo of the suicide bombings that killed 52 passengers on the network two weeks earlier.

The jury on Monday unanimously found Muktar Said Ibrahim, 29; Yassin Omar, 26; Ramzi Mohammed, 25; and Hussain Osman, 28, guilty of conspiracy to murder. They face sentencing on Wednesday.

All six defendants denied the charges, saying the devices were duds and their actions a protest against the Iraq war. But police and prosecutors said scientific tests proved the bombs were all viable. They do not know why they did not work.

During the six-month trial, prosecutors say Asiedu lost his nerve and abandoned his device in a London park. Yahya left Britain for Ethiopia several weeks before the attacks.

During the trial, Asiedu turned on the others and claimed Ibrahim, the gang's self-proclaimed leader, had wanted the attacks "to be bigger and better" than the July 7 bombs.

The four attempted to detonate explosives-laden backpacks on three subway trains and a bus, as in the July 7, 2005, attacks. The devices — made from a volatile mix of hydrogen peroxide and flour — failed to explode, and no one was injured.

Unlike three of the four July 7 bombers, who were British-born, those in the July 21 plot had come to Britain as young men from places like Eritrea, Ethiopia and Somalia. Some had become British citizens, others had refugee status.