The attacks occurred as 15 suspects with alleged links to al Qaeda are being tried for a wave of violence earlier this year that left at least 47 people dead. Those attacks included Central Asia's first-ever suicide bombings.
"I think the prime suspect has to be the IMU - which is the Islamic Movement of Uzbekistan. This is an Islamic extremist outfit closely linked to Osama bin Laden and al Qaeda," M.J. Gohel, a terrorism expert with the Asia Pacific Foundation told CBS Radio News.
The U.S. Embassy said a suicide bomber detonated a bomb outside its building and that two Uzbek police officers were also injured. No American or local embassy personnel were hurt, the embassy said in a statement.
Israeli Ambassador Tzvi Cohen told Israel Radio there was a blast at his embassy, but "it's still not clear if it was an explosive device or a suicide bomber." He said the two dead were local Uzbek workers.
Cohen said the explosion occurred on the street outside the embassy entrance, and that all the Israeli personnel were safe inside the building.
"Because the targets were U.S. interests and Israeli interests, obviously the security in Uzbekistan is not that good, so these were soft targets in that sense," Gohel said.
A spokeswoman for the general prosecutor's office, Svetlana Artikova, said there also was a blast at that building, but had no information on casualties. Russia's Interfax news agency reported there were deaths in the blast, citing an unnamed source at the office.
Uzbekistan, a former Soviet republic bordering Afghanistan, became the United States' key ally in the region after the Sept. 11 attacks, hosting hundreds of U.S. troops at a military base near the Afghan border. Uzbek President Islam Karimov runs a strict regime that has sought to wipe out Islamic extremism and allows no opposition to his rule, which dates to Soviet times.
The Central Asian nation is a little larger than California and home to 25.9 million people, according to the CIA World Factbook. It is 88 percent Muslim.
Outside the heavily fortified American compound, a body believed to be that of a suicide bomber lay across the street from the entrance. The tall security wall surrounding the compound appeared to be scarred with black burn marks, and area was blocked off by heavily armed police and soldiers.
Nargiza Usmanova, who operated a flower kiosk down the street, said the "building jumped" when the explosion went off. She said she had seen several people lying in the street after the blast, and that they were still moving their hands.
Debris littered the street outside the Israeli Embassy, also under heavy guard. A window appeared to have been broken, but the tall wall protecting that building also didn't appear to suffer any serious damage.
A nearby resident who said he arrived at the scene before police, Konstantin Ivanov, said he saw four severed hands lying in the street. He ran to the scene after hearing the blast, which he said sent a large cloud of smoke into the air.
Many Jews have left Uzbekistan since the 1991 Soviet collapse, but it is still home to a sizable community.
The 15 suspects on trial for the March and April violence that killed 47 have pleaded guilty to charges of terrorism, murder and religious extremism and could face the death penalty.
Several of the suspects have said the U.S. and Israeli embassies had been intended targets in the wave of explosions that officials say killed 33 alleged militants, 10 police and four bystanders.
In testimony at the trial that started Monday, defendants described a network of Islamic extremists extending into Pakistan's lawless tribal areas, where they said would-be militants were trained in shooting and how to use airplanes in attacks.
They claimed to belong to an extremist group called Jamoat, which means "society" in Uzbek, whose leader previously fought with the al Qaeda-connected Islamic Movement of Uzbekistan. However, he broke ties with the IMU in forming the new group.
Early Friday, Pakistani officials announced the arrest of al Qaeda suspect Ahmed Khalfan Ghailani, whose wife is Uzbek. Ghailani was wanted in connection with the 1998 bombings of the U.S. embassies in Kenya and Tanzania.