The 2007 bomb plot in Germany, planned by the al-Qaeda controlled Islamic Jihad Union (IJU), affiliated Sauerland terror cell (German: Sauerland-Gruppe, lit.'Sauerland Group'), was discovered following an extensive nine-month investigation. That involved more than 600 agents in five German states. The number of agents involved in a counterterrorism operation led by the federal police has never been the case before. At the same time, Danish police in Copenhagen were busy with explosives. A Pakistani and an Afghan man have been charged with preparing to carry out their attacks under al-Qaeda plans. Authorities said they were unaware of any direct links between the terrorists arrested in the two European countries. Three men were arrested on 4 September 2007 while leaving a rented cottage in the Oberschledorn district of Medebach, Germany where they had stored 700 kg (1,500 lb) of a hydrogen peroxide-based mixture and 26 military-grade detonators, and were attempting to build car bombs. A supporter was arrested in Turkey. All four had attended an IJU-training camp in the border region between Afghanistan and Pakistan in 2006. They were convicted in 2010 and given prison sentences of varying lengths; all have since been released.

Al-Qaeda (; Arabic: القاعدة al-Qāʿidah, IPA: [ælqɑːʕɪdɐ], translation: "the Base", "the Foundation", alternatively spelled al-Qaida and al-Qa'ida), officially known as Qaedat al-Jihad, is a multinational militant Sunni Islamic extremist network composed of Salafist jihadists. It was founded in 1988 by Osama bin Laden, Abdullah Azzam, and several other Arab volunteers during the Soviet–Afghan War.Al-Qaeda has been designated as a terrorist group by the United Nations Security Council (the permament members of which are China, France, Russia, the United Kingdom and the United States), the North Atlantic Treaty Organization (NATO), the European Union, India and various other countries (see below). Al-Qaeda has mounted attacks on non-military and military targets in various countries, including the 1998 United States embassy bombings, the September 11 attacks, and the 2002 Bali bombings.The United States government responded to the September 11 attacks by launching the "war on terror", which sought to undermine al-Qaeda and its allies. The deaths of key leaders, including that of Osama bin Laden, have led al-Qaeda's operations to shift from top-down organization and planning of attacks, to the planning of attacks which are carried out by a loose network of associated groups and lone-wolf operators. Al-Qaeda characteristically organises attacks which include suicide attacks and the simultaneous bombing of several targets. Al-Qaeda ideologues envision the violent removal of all foreign and secular influences in Muslim countries, which it perceives as corrupt deviations.Al-Qaeda members believe a Christian–Jewish alliance (led by the United States) is conspiring to be at war against Islam and destroy Islam. As Salafist jihadists, members of al-Qaeda believe that killing non-combatants is religiously sanctioned. Al-Qaeda also opposes what it regards as man-made laws, and wants to replace them exclusively with a strict form of sharīʿa (Islamic religious law which is perceived as divine law).Al-Qaeda has carried out many attacks on people whom it considers kāfir. It is also responsible for instigating sectarian violence among Muslims. Al-Qaeda regards liberal Muslims, Shias, Sufis, and other Islamic sects as heretical and its members and sympathizers have attacked their mosques, shrines, and gatherings. Examples of sectarian attacks include the 2004 Ashoura massacre, the 2006 Sadr City bombings, the April 2007 Baghdad bombings and the 2007 Yazidi community bombings.Following the death of Osama bin Laden in 2011, the group has been led by Egyptian Ayman al-Zawahiri, and as of 2021 has reportedly suffered from a deterioration of central command over its regional operations.