Syrian official news agency, SANA, reported the terrorists detonated an explosive device on the bus in Wadi al-Dhahb district in the southeastern part of Homs on Tuesday.
Reuters quoted a witness as saying that the explosion left one person dead and two others wounded.
No group has claimed responsibility for the blast, which came a day after the foreign-sponsored Takfiri militants reached an agreement with the Syrian government for the imminent evacuation of civilians and extremists from a neighborhood in Homs.
Provincial Governor Talal Barrazi said the militants would be allowed to leave al-Waer in Homs, located 162 kilometers north of the capital, Damascus, under a Russia-backed deal signed on Monday.
Barrazi added that the deal would be carried out within six to eight weeks, with the first group leaving on Friday.
Waer is the last militant-held neighborhood in Homs. It is home to about 75,000 people and has been under a government siege since 2013.
According to SANA, the evacuation is the third phase of a deal struck last year that saw hundreds of militants and their families leave al-Waer for other opposition-controlled areas in Homs Province, the northwestern province of Idlib, and the town of Tal Abyad near the border with Turkey.
Last month, simultaneous bombings targeted separate areas across the western city, claiming a total of 42 lives. Some reports said the fatalities included a senior security official, named Hossein Da’aboul.
Responsibility for the attacks was later claimed by the al-Nusra Front terrorist group.