Four London Subway Station & Bus Explosions (Updated)
NOTE: Last edit in this post at 10:00 pm Eastern time. Fox News: London Police confirm four explosions or "attempted explosions" with only one report of injury. Sky News has bus eyewitness accounts and reports "Chemical searches at all four sites have proved negative." BBC has running chronology of today's incidents - note they started at lunchtime - and here is London Police's first statement.
London Police press conference: Four unexploded devices. Forensics provide possible "significant breakthrough" and ask for tips to THIS WEB ADDRESS. Can't provide bombers' description yet. Can't confirm/deny "nail bomb" story, and two arrests "entirely unrelated." Can't attribute to Al Qaeda yet. No transported casualties, and one reported casualty might be unrelated. PM Blair encourages calm and a return to normal soon and thanks Australian PM John Howard for strong support on security issues. BBC website: "A police source says officers are looking for an unknown number of fugitives." NBC News: "British authorities told their U.S. counterparts that the backpacks used in Thursday's planned attacks and the explosives found in the backpacks are identical to those used in the July 7 attacks — evidence that strongly suggests the two sets of attacks were connected." Another BBC site: "Bomb disposal officers are examining a rucksack on the top deck of a bus evacuated after an explosion. A police officer at the scene told BBC News the driver had found the black rucksack split open on the top deck and they were treating it as suspicious." Also on BBC: "Armed police officers have searched a hospital close to the scene of one of four attempted explosions. Staff at University College Hospital were told in an e-mail to look for a man with wires protruding from his top...Three rooms in an unoccupied part of the hospital remain cordoned off...Police said there had been no arrests in connection with Thursday's four attempted explosions at three Tubes and on a bus." Sky News: "No one has been arrested directly in connection with the blasts. Two earlier arrests are not believed to be linked."
CT Blog Experts doing numerous TV appearances - Evan Kohlmann on NBC: Jihad supporters on Internet "rallied" by second attacks and notes Algerian GSPC's support. Matthew Levitt on NPR this morning. Walid Phares on MSNBC: Split exists in Islamic world on use of terrorist tactics; 80-85% of Muslims reject terrorism, but many terrorism backers. Steven Emerson on Fox News today (today's failure not symptomatic of Al Qaeda - forensics will reveal how connected to 7/7 attacks - obviously British government hasn't found all explosives within country) and on "O'Reilly Factor" at 8 pm Eastern, John Batchelor's radio show at 9:20 pm Eastern, and MSNBC's "Scarborough Country" at 10 pm Eastern. See Daveed Gartenstein-Ross's initial comments here and is on RadioAmerica at 6:50 pm Eastern time tonight. Doug Farah on Fox News this afternoon (Discussed Pakistan arrestee and small-dollar transfers) and Zeyno Baran on Fox News tomorrow.
Speculation among experts begins at various news sites - London Times - AP story - see London Times story on possibility of same cell as 7/7 attacks. Roger Cressey, former NSC CT official, describes unexploded devices as "jackpot" for investigators.
This site has numerous 7/7 & 7/21 attack pictures submitted by witnesses.
NY Police Commissioner Kelly announces random bag checks on NYC subway starting today. Pentagon security heightened.

