The Syrian state news agency called the Aleppo explosion a "terrorist bombing" and said one policeman and one female civilian were killed, while 30 were injured. It was the second attack in two days on regime strongholds. Three suicide bombings killed 27 people in Damascus on Saturday.
Meanwhile, opposition groups in Syria called for protests to mark the one-year anniversary of the first nationwide demonstrations of the country's uprising.
Many activists consider March 18 the start of the protests against President Assad. The United Nations said more than 8,000 people have died in the last year.
The Associated Press contributed to this report.