https://www.cia.gov/library/abbottabad-compound/EE/EE3F72AC1E60924DF25CA4EB3562BD8F_Al_Qaeda_has_Nuclear_Weapons.pdf

Mir's position that al-Qaeda's nuclear weapons may have already been forward deployed to the United States confirms the report of Sharif al-Masri, a key al-Qaida operative who was arrested in Pakistan in November 2000.

Al Masri, an Egyptian national with ties to al-Zawahiri, said that al-Qaeda had made arrangements to smuggle nuclear weapons and supplies to Mexico, From Mexico, he said, the weapons were to be transported across the border and into the United States with the help of a Latino street gang.

Mir also maintains that numerous sleeper agents are in place in major cities throughout the United States to prepare for the nuclear holocaust. Many of these agents, he says, are Algerians and Chechens who obtained European passports and are posing as Christian and Jews. He further says that many of these agents have been in the United States since bin Laden's issuance of his "Declaration of War on Americans Occupying the Country of the Two Holy Places." That fatwa was issued Aug. 23, 1996

https://articles.latimes.com/2002/jul/19/opinion/oe-chuen19

Russia's nuclear submarines also provide a tempting terrorist target. In 1998, a disgruntled sailor overpowered a guard and barricaded himself in the torpedo compartment of a Northern Fleet Akula-class submarine. He died attempting to set a fire.

A fire beneath the torpedoes would have led to the explosion of all of the submarine's ammunition, which would have destroyed the submarine, neighboring nuclear submarines and the port town of Gadzhiyevo, not to mention the greater consequences of destroying the nuclear reactors.

Terrorists too have toyed with the idea of taking over a Russian submarine: In February, the Russian military discovered plans to hijack a Russian nuclear submarine. The plan, prepared by Islam Khasukhanov, chief of staff of the Chechen armed forces and a former deputy commander of a Soviet nuclear submarine, called for seven people of Slavic origin to board a submarine and place explosives in the torpedo, battery and reactor compartments as well as near the warhead of one of the missiles.