Government warplanes, helicopter gunships and artillery were bombarding rebel-held parts of the city and its suburbs, according to the Britain-based Syrian Observatory for Human Rights and Aleppo-based activist Bahaa al-Halaby.
The pro-government Addounia TV said one person was killed and five people were wounded by mortar rounds fired by insurgents into the predominantly Kurdish Sheikh Maqsoud district of the city.
The fighting came a day after Syrians in government-held parts of the country voted for a new parliament - balloting that the opposition has dismissed as a sham and that could further undermine the peace talks.
Aleppo has seen sporadic clashes despite a US-Russia-engineered truce that went into effect in late February. Government forces and their allies have rebel-held parts of Aleppo almost surrounded from all sides, except for a corridor from the northwestern edge of the city.
Also Read
"Areas close to the front lines are tense," said al-Halaby, the activist, speaking via Skype as explosions were heard in the background. He said several shells are falling every minute on the city and its suburbs.
Meanwhile, the US-led coalition struck areas controlled by the Islamic State group near Syria's border with Turkey, according to a Turkish news agency. The militant IS group and al-Qaida's Syria branch known as Nusra Front are not part of the cease-fire in Syria.
Coalition jets struck Islamic State militants in the villages of Souran, Hawar Kilis and Kafra, reported the private Dogan news agency. The report said smoke rose from the strikes and that sounds of explosion and gunfire were heard from across the border.