¡¡LONDON, July 22 (Xinhuanet) -- A group linked to the al Qaeda terrorist organization has claimed responsibility for Thursday's bombings in London, as forensic teams are examining the rucksack bombs found on a bus and in underground trains.

    The group named as Abu Hafs al Masri Brigade, also claimed responsibility for the explosions on July 7, the Sky news television reported Friday.

    But the authenticity of the statement was not verified yet.

    Turki al-Faisal, Saudi Arabia ambassador to London, was quoted by Sky news as believing that Thursday's attacks are linked to Osama bin Laden's al Qaeda network.

    "The modus operandi, the sheer cowardice associated with them and the attacks on innocent civilians - these are all part and parcel of al Qaeda," he said.

    On Thursday, four explosions took place almost simultaneously at three underground stations and a No. 26 bus in east London.They mirrored the attacks two weeks ago, in which more than 56 people were killed and over 700 people injured in blasts on three underground railway trains and a bus in London.

    Three of the four devices found on Thursday are thought to be ofa similar size and weight to the bombs used in the July 7 attacks.The fourth was smaller and appears to have been contained in a small plastic box.

    Police said the device on the bus was in a newish-looking black Fitness First rucksack. Officers found it in a footwell on the topdeck of the double-deck bus. On the seat next to the rucksack they found a Duracell battery and some red wire.

    Police received reports of people running away from two of the attempted blast sites.

    At least two people were arrested on Thursday afternoon, including one in Downing Street, but they were released later without charge.

    Reports suggested that only the detonators on the four devices went off. Detectives investigating the attacks are working on the basis that the bombs were not properly primed.

    Police are appealing for witnesses to come with evidence and statements to several locations or call anti-terrorist hotline. They are also asking people with photos or mobile phone images from any of the incident scenes to send them on-line. Enditem