A teenage girl and a man in his 20s were killed on the spot and three people suffered serious wounds, police said, adding that a manhunt has been launched for the assailant. "All indications point that this was a criminal incident and not a terror attack, which was most likely deliberately directed against the gay and lesbian community," police spokesman Micky Rosenfeld told AFP.
Thousands of people gathered in the city centre overnight to protest at the attack, some waving rainbow banners and lighting candles for the victims.
"Our (gay) community won't let itself be frightened, it will stand up to those who threaten it with heads held high and with pride, we will respond to war with war," left-wing opposition Meretz party MP Nitzan Horowitz said. The victims were identified Liz Tarabushi, 17 and Yaniv Katz, 26.
Police have imposed a complete blackout on details of the inquiry, but investigators were seen sifting through evidence at the scene while bloodied victims were taken by stretcher into ambulances.
Tel Aviv police chief Shahar Ayalon ordered the closure of a nearby gay bar and urged such establishments to remain vigilant. "We are only at the first stage of the investigation, we continue our search and we are not sure of the motive of this attack since the centre has not received any threats recently," Ayalon said.
If the motive is confirmed, it would be the worst homophobic attack against Israel's gay and lesbian community. "It is not surprising that such a crime can be committed given the incitement of hatred against the homosexual community," the president of Tel Aviv's gay and lesbian community, Mai Pelem, told reporters.
Pelem was referring to verbal attacks against gays from the religious community in Israel, where homosexuals, particularly men, often encounter hostility from ultra-Orthodox Jews who consider sexuality an "abomination." In the past, swastikas have been painted at the entrance to the centre in an attempt to stigmatise homosexuals.
"In our worst nightmares we could not have imagined that the hatred against our community, which is hurting nobody, could go this far," the head of Israel's gay and lesbian national association, Mike Hamel, told journalists.
Internal Security Minister Yitzhak Aharonovitch also said he believed the attack had homophobic motives and promised the police would do everything possible to arrest the gunman, military radio reported. "Tel Aviv-Jaffa has always been a bastion for pluralism, tolerance and openness, Tel Aviv mayor Ron Huldai said in a statement. "But no one will manage change the city's character. We will continue to offer the gay community a warm house in our city and fight for everyone's right to live according to his faith and beliefs."
In 2005, an ultra-Orthodox Jew stabbed three participants of the gay pride parade. He was later sentenced to 12 years in prison. Israel repealed a ban on consensual same-sex sexual acts in 1988 and certain rights of gay or lesbian couples have since been recognised by the courts.