The Iraqi ambassador said the device was in a package placed in front of the entrance of his residence but that neither he nor the embassy had received any threats, Iran's semi-official Fars News Agency said.
"There has never been a threat against me or the Iraqi embassy in Tehran and we don't suspect any group," the envoy, whose name was given as Mohammad Majid al-Sheikh, told Fars.
Iraqi Prime Minister Nuri al-Maliki left the Iranian capital on Monday following a three-day visit.
Iran and Iraq fought an eight-year war in the 1980s but ties between the predominantly Shi'ite Muslim countries improved after Sunni Arab leader Saddam Hussein was toppled in the U.S.-led invasion of Iraq in 2003.
"Nine o'clock last night when my driver went to our residence he saw a suspicious package in front of the entrance and he quickly informed the police and fire department," the ambassador said.
"After the police came it became clear that the package contained a bomb and quickly the street leading to the residence was blocked and all the necessary actions started," he said.
(Reporting by Zahra Hosseinian; Writing by Fredrik Dahl; Editing by Elizabeth Piper)
