LONDON -- British government reports into the July bombings on London's transit network conclude the four attackers acted without the assistance of foreign terrorists, officials and lawmakers said Wednesday.

The two reports being released today address concerns that intelligence agencies had placed two of the bombers under surveillance in 2004 but determined them not to be a threat and halted the supervision.

Authorities have long held that the four men, who killed 52 subway and bus passengers, were homegrown terrorists who acted independently and not at the direction of an al-Qaida operative or other foreign group.

Exhaustive investigations now support that assessment, a government official said, speaking on condition of anonymity because the report is yet to be released.

But the reports, by Britain's Home Office and a committee of lawmakers, are likely to fuel further calls for a broader probe that would publicly dissect the evidence, called for by survivors of the attacks and opposition lawmakers.

Britain's Home Office attempted to examine the ease with which the attack was mounted and the effect the 2003 U.S.-led invasion of Iraq had in radicalizing young British Muslims to strike against their homeland, the official said.

The Home Office report was written as an alternative to a full public inquiry. Government officials claimed such a probe would divert attention from the continuing investigation, distract from work to counter potential future threats, and take too much time.

In compiling a separate report also being released today, Britain's parliamentary Intelligence and Security Committee interviewed the heads of Britain's two spy agencies, investigating if more could have been done to prevent the attacks, the official said.

It is expected to conclude there is no evidence the agencies could have prevented the attack, even as it highlights problems caused by a lack of resources, main opposition Conservative Party homeland security spokesman Patrick Mercer said.

Survivors of the bombings are campaigning for a public inquiry similar to the U.S. commission into the Sept. 11, 2001, attacks.

"We've waited 10 months for these two reports and I don't think they will answer the questions I have or that others have," said Rachel North, a 35-year-old strategy director who survived the bombing of a subway car at Russell Square station, which killed 26 people.

"We need a public inquiry, because if we have reached a stage in Britain where young men think their only option is to destroy themselves and others, we have serious problems," North told The Associated Press.

North said the government must publicly address the circumstances that have allowed "horrible ideologies" to win favor in Britain.