(CNN) -- Syrian military airstrikes hit parts of the country's largest city Thursday, killing at least 33 people and injuring several others, the UK-based opposition group Syrian Observatory for Human Rights said.
The airstrikes were the latest in a string of attacks reported in Aleppo, the northwest Syrian city that has been a hotly contested area in Syria's civil war.
A day earlier, Syrian forces dropped barrel bombs on an opposition-held area of Aleppo, killing 25 children, according to the opposition Local Coordination Committees of Syria.
The unrest comes amid Syria's three-year civil war pitting government forces against rebels trying to end the rule of Syrian President Bashar al-Assad.
The government intends to hold elections June 3. Al-Assad, whose family has had a tight grip on power for 43 years, is running for another term.
The United Nations is asking the government to reconsider the election because of the war. More than 100,000 people, including many civilians, have been killed, according to the United Nations.
Al-Assad succeeded his father in 2000 and won a second term in 2007, unopposed.