According to the police report, a man entered a hotel located on the fourth floor of a building across from the synagogue at around 3 a.m. and as he was checking in, abruptly threw his suitcase out the window.
The case contained four containers of gasoline each attached to a glass bottle of sulfuric acid meant to shatter on impact and ignite the makeshift bomb, said police, who speculated the man may have panicked.
The bag, which also contained clothes, cotton strips, matches and a lighter, fell onto the sidewalk in front of the hotel and briefly caught fire before being extinguished. There were no injuries and no damage to the historic synagogue.
The suspect fled the scene and is now being sought by police.
Egypt's once thriving Jewish community largely left the country 50 years ago during hostilities between Egypt and Israel, but a number of heavily guarded synagogues, open only to Jews, remain.
The downtown synagogue, Egypt's largest, is the only one still conducting services for the Jewish high holidays, which are sometimes attended by Israeli diplomats.
The temple, known as Shaar Hashamayim, or the Gate of Heaven, was built in 1899 in a style evoking ancient Egyptian temples and was once the largest building on the wide downtown boulevard.
Egypt's Jewish community, which in the 1940s numbered around 80,000, is down to several dozen, almost all of them elderly.
Egypt and Israel fought a war every decade from the 1940s to the 1970s until the 1979 peace treaty was signed.
Since the 1990s, there have been few organized terrorist attacks in Egypt's Nile valley and the capital Cairo. There have, however, been a number of amateurish attempts to target foreigners over the years.
In February 2009 a crude explosive device planted in a bazaar popular with tourists killed a French teenager.
