No evidence to link London attack directly to militant groups - US sources

LONDON - British police and spy agencies have not found evidence that last week's attack on a London commuter train was ordered or organized by a recognized militant group, according to US and British government sources familiar with the investigation.
Counterterrorism officers have arrested two men after a crude homemade bomb sent flames shooting through a packed carriage at west London's Parsons Green underground station during the Friday morning rush hour, injuring 30 people although it apparently failed to detonate fully.
Following the attack, Amaq, the news agency of the Islamic State militant group, claimed responsibility for the bombing.
On Monday, five US and British government sources said it was possible that the attack was somehow "inspired" by Islamic State via its extensive array of internet-based propaganda and instruction materials.
But they said no evidence had emerged of any direct connection between the attack and IS, or any other organized militant group or faction.
"It doesn't sound to me like a centrally directed plot," one official said.
British police are questioning an 18-year-old man arrested in the departure lounge of the port of Dover on Saturday and another suspect, 21, detained hours later in the west London suburb of Hounslow.