Muslim anger over the Israeli military offensive into the Gaza Strip has prompted London to go onto its highest state of alert, rated as “severe,” since the attacks of September 11, 2001, the London Daily News has reported. Protests outside the Israeli embassy turned violent in recent days as the conflict as escalated.

The report said that the United Kingdom’s domestic intelligence service, MI5, has listed the possible methods terrorists could use to attack the country as explosive devices, shootings, kidnappings, surface-to-air missiles, weapons of mass destruction, or other methods.

The alert comes as one British official warned that MI5 “was still too under funded and undermanned to cope with the task they face in the decades to come. And that's how long this will last."

London suffered its last major terrorist attack on July 7, 2005 when radical Islamic terrorists suicide bombed subways and a bus, killing 52 civilians and injuring over 700. The second-in-command of Al-Qaeda, Ayman al-Zawahiri, claimed his organization was behind the attack.