Faced with two sinister attacks on Israeli tourists in Kenya, hardline Prime Minister Ariel Sharon tasked Israel's elite spy service, the Mossad, Friday to hunt down the killers.

"We will not give in to terror ... Israel will go after those who spilled the blood of its citizens," Sharon promised in Tel Aviv.

The Mossad was on the prowl for the masterminds behind the hotel car-bombing and a failed missile strike on an Israeli jet in the coastal city of Mombasa.

Over the decades, the agency has earned a reputation for dazzling capers as it doled out street justice on behalf of the Jewish state.

Founded in 1951, three years after Israel's creation, the Mossad includes an elite "action unit" assigned with the delicate and discreet task of neutralising the state's foes.

The agency counts 2,000 to 3,000 agents and is the smallest branch of Israel's security service. It reports directly to the prime minister as does Shin Beth, the domestic intelligence service.

The Mossad cemented its legend in 1960 when it abducted Nazi war criminal Adolf Eichman from Argentina and brought him back to Israel where he stood trial and was executed.

The agency's myth soared in the 1970s after it hunted down and methodically picked off one by one the leaders of the Palestinian group Black September, responsible for the deaths of 11 Israeli athletes at the 1972 Olympic Games in Munich.

In October 1995, the head of the Palestinian militant group Islamic jihad , Fathi al-Shikai, was gunned down on the streets of Malta. The professional hit, though never formally claimed, had all the trademarks of the Mossad.

However, once known for its sure touch, Mossad has stumbled in recent years.

The agency's biggest bungle was the botched 1997 assassination in downtown Amman of Khaled Meshaal, the head of Hamas' political wing. Two Mossad agents, posing as Canadian tourists, injected Meshaal with lethal chemicals before being knabbed by his bodyguards and handed over to police.

In exchange for the release of the two agents, Israel released Hamas' founder and spiritual leader Sheikh Ahmed Yassin later that year.

The Mombasa attacks, which killed three Israelis, are the first real test for Israel's new spy chief, Meir Dagan, who took office on October 30.

A reserve army major general, Dagan, 55, has served as a political advisor to Sharon.

He had also been close to Sharon's main Likud rival Benyamin Netanyahu, serving as his anti-terrorism advisor when he was premier from 1996 to 1999.

In November 2001 he was tasked with overseeing ceasefire talks with the Palestinians to quell their uprising, which started 14 months earlier.

Israeli media credit Dagan with drafting a document on the removal of Palestinian leader Yasser Arafat from the political stage. The plan called for the gradual isolation of Arafat at home and abroad, the reports said.

Dagan headed an elite commandos unit in 1970 that presided over the summary execution of Palestinians suspected of leading attacks against Israeli forces in the Gaza Strip.AFP