And Uzbek President Islam Karimov cut short his vacation in the Crimea and is returning home to head the investigation into the bombings.
Israel's ambassador to Uzbekistan, Tzvi Cohen, says at least two Uzbeks were killed in the explosion outside the Israeli Embassy.
Uzbek state television cited the Interior Ministry as saying a policeman and a member of the Uzbek National Security Service were killed.
Israeli radio initially reported that the blast at the Israeli Embassy was caused by a suicide bomber. But Cohen later said that report could not be confirmed.
RFE/RL correspondent Sadriddin Ashurov was in the area of the Israeli Embassy at the time of the explosion and said it does not appear as if the Israeli Embassy building itself was damaged.
"I saw two or three ambulances arriving at the site when I was there," Ashurov said. "The people whom I talked to said there might have been casualties, but they didn't know who or how many. The explosion took place outside the building, and as far as I know it wasn't damaged."
Israeli radio reports that all Israeli personnel were safe inside the embassy building at the time of the blast. Uzbek security forces are conducting searches of the area.
Uzbek Interior Minister Zakirjon Almatov and Prosecutor-General Rashid Kadyrov sid at least five people were injured in the explosion at the Prosecutor-General's Office. Almatov and Kadyrov say a male suicide bomber entered the lobby of the building and detonated his explosives.
Witnesses also said a suicide bomber was responsible for the attack at the U.S. Embassy. They said a man entered the guard booth outside the embassy and exploded his bomb.
One witness, a merchant at a local market close to the U.S. Embassy, described what he saw: "It happened at 4:45 p.m. [local time] while I was doing my business. The explosion was so strong that one could see a flame. But I didn't manage to get through to the place where it happened."
An employee at the U.S. Embassy told RFE/RL that people outside the embassy compound were injured in the explosion, but that no one from the embassy was hurt.
The bombings come as trials are under way in Tashkent and in Karshi involving terrorism suspects.
The Tashkent court proceedings are against 13 men and two women who are suspected of being involved in suicide bombings and attacks on law enforcement officers in the western Uzbek city of Bukhara and in Tashkent in late March and early April.
Forty-seven people were killed in those attacks -- 33 of them the attackers.
(RFE/RL and agency reports)