A crack unit of Israeli commandos was airlifted to Kenya as soon as the Westgate Mall siege began, as Nairobi invoked a secret security pact between the two countries under which Jerusalem guarantees military assistance should the Kenyan government be threatened by a foreign force.

Israeli special counter-terrorism forces tasked with hunting down the 20 or so al-Shabaab insurgents holed up in the Westgate Mall are locked in the first battle between the Jewish state and al-Qaida terrorists on foreign soil. The Israeli foreign ministery refused to confirm or deny any involvement in Kenya.

According to the Jerusalem-based DEBKAfile, an Israeli intelligence website, the US has also sent a commando unit to Nairobi from bases in Italy and the UK has dispatched an advance counter-terrorism forward team. The Cobra cabinet is holding sessions in London as the situation unfolds.

The Israeli army and security bodies send combat equipment and provide tactical advice to Kenyan units fighting alongside Somali government forces against al-Shabaab; and Israel's intelligence agencies and police are helping the Kenyan government build a barrier against the Somali war's spillover, to guard against al-Shabaab opening up a second front to the rear of the Kenyan forces fighting across the border, claims DEBKAfile. It notes that this protective barrier clearly sprang a large leak in the case of the Westgate Mall.

Coincidentally, the Westgate Shopping Mall is owned by an Israeli company.

The attack by a cell of up to 20 Islamic insurgents began on a busy Saturday lunchtime, when they opened fire with AK-47s and a volley of grenades. As families of wealthy Kenyans and expatriates fled, 59 were killed and hundreds injured. Muslims were allowed to go free.

An unknown number of hostages, among them British citizens, are still inside the shopping centre. Three Britons are among the dead.

The assault was the biggest single attack in Kenya since al-Qaida's East Africa cell bombed the US Embassy in Nairobi in 1998, killing more than 200 people. In 2002, the same militant cell attacked an Israeli-owned hotel on the coast and tried to shoot down an Israeli jet in a coordinated attack.

Kenya is Israel's closest ally in Africa. In the raid on Entebbe in 1976 to free a planeload of hostages being held at the Ugandan airport by Palestinian hijackers, the Kenyans allowed Israeli planes carrying paratroops to refuel at Nairobi's international airport.