A suicide bomber who killed three Israelis at a Tel Aviv nightclub today entered Israel using a British passport, as did an accomplice who apparently fled the scene, police said.
"The two terrorists are British nationals who entered Israel from the Gaza Strip," a police spokesman said.
"One blew himself up...and the other failed to set off his load and managed to escape after scuffling with onlookers and dumping the bomb. A manhunt is on and we appeal to the public for help."
Israel's Channel 2 television broadcast images of the documents which bore the names of Asif Hanif (21) the alleged bomber, and Omar Sharif (27). Accompanying photographs showed two young men of Middle Eastern appearance.
The Islamic militant group Hamas claimed responsibility for the attack, saying it acted with the al-Aqsa Martyrs Brigades, an offshoot of Palestinian President Yasser Arafat's Fatah movement.
Both have spearheaded attacks in a 31-month-old Palestinian uprising for independence in the West Bank and Gaza.
In London, a British Foreign Office spokesman said: "We are aware of the reports. We are in regular contact with Israeli security services. We have no comment to make on this particular allegation."
Israeli security sources said Israel's domestic intelligence service, the Shin Bet, had been on the lookout for possible infiltration by pro-Palestinian militants using Western passports.
At least half a dozen foreigners are in Israeli jails after being convicted as "sleeper agents" for the guerrilla group Hizbollah, which hastened the end of Israel's 22-year occupation of southern Lebanon in 2000 and backs the Palestinian revolt.
Hizbollah denies involvement in Palestinian militancy. But in May 2002 it admitted attempting to smuggle arms into the West Bank through Jordan.