A witness, who pleaded anonymity, disclosed that the incident took place at about 9p.m at the Rendezvous Hotel on Uche Road in Sabon Gari.
He said the incident left several other persons injured.
The security situation in Zaria had deteriorated in the last few days, following the presence of suspected members of Boko Haram in the town.
Confirming the incident, the Army Public Relations Officer, Depot Nigerian Army, Capt. Ibrahim Abdullahi, said security agencies had already rallied round to take control of the situation.
He, however, said the extent of damages done by the explosion was yet to be ascertained.