The clearly coordinated blasts in the capital Tashkent on Friday came four days after the authoritarian former Soviet state, a US ally in the "war on terror", put 15 suspected al- Qaida followers on trial for bomb attacks in March that killed nearly 50 people.
The Islamic Movement of Uzbekistan (IMU), which has staged previous deadly attacks in the republic, claimed responsibility, according to an Islamist internet site, reported news agency AFP.
"A group of young Muslims from the Islamic Movement of Uzbekistan carried out martyrdom operations today against the embassies of America and Israel and the office of the prosecutor general, which started a few days ago to try several brethren from the group," the agency quoted the statement as saying.
However, Aljazeera's correspondent in Moscow reported the IMU was neither known in Uzbekistan nor in Russia. This had put a question mark on who had actually carried out the attacks.
(Reuters, quoting an Islamic website said the "little-known" Islamic Jihad group in Uzbekistan had claimed responsibility.)
One bomber targeted the lobby
of the state prosecutor's office
There was also speculation that the relatives of detainees - who are under trial for the March attacks - were responsible for the blasts and an act of revenge. The suspects were accused of being members of the Islamic Liberation Party (ILP), reported Aljazeera's correspondent.
US and Israeli officials said the three bombers seemed to have approached the buildings on foot as business was winding up for the day.
"One policeman and one security guard who were guarding the embassies were killed. Nine people were injured. Two of them are in a serious condition," the Uzbek Interior Ministry said.
An Israeli security source said: "The attacker came as close as possible to the door, saw the Uzbek security men and then detonated himself."
Sources said one of the dead was the ambassador's personal bodyguard, the other an embassy guard.
Body parts and flesh lay outside the embassy and windows were shattered in houses opposite.
Israeli ambassador Zvi Cohen said he and three other Israeli officials were in the building at the time along with two local security guards. Security had been stepped up since the earlier bombings wrought havoc in Uzbekistan in March.
"The attacker came as close as possible to the door, saw the Uzbek security men and then detonated himself"
Israeli security source
A man blew himself up in the lobby of the prosecutor's office, wounding five people, Interior Minister Zakirdzhon Almatov said.
A US embassy spokeswoman said there had been no injuries confirmed among staff there. The bomb had detonated outside.
Brook no challenge
The three buildings targeted are spread across the modern city of two million, located in the heart of arid Central Asia.
President Karimov, who has brooked no challenge to his rule since Communist times, was visiting Ukraine's Crimean peninsula, but would rush home overnight, local officials said.
Uzbekistan's 26 million people are mostly Muslim. The president tolerates only state-sponsored clerics in mosques and has cracked down on unauthorised religious activity.
He has won support from the US by allowing American troops to set up a base in the country, but his human rights record has caused controversy in Washington, which this month suspended aid to Tashkent because of rights abuses.