BEIRUT -- Airstrikes on rebel-held parts of the northern city of Aleppo killed at least 14 people Tuesday, and the shelling of a government-held neighborhood in southern Syria hit a school, killing at least six, including children, opposition activists and state media said.
The state-run Syrian Arab News Agency also reported shelling of neighborhoods in the capital, Damascus, including several mortar shells, fired by opposition groups on the edge of the city, that landed in the residential Qasaa district and close to the Umayyad Mosque, wounding an unspecified number of people.
Fighting on a number of fronts across the country has intensified in recent weeks after the collapse of a U.S. and Russian-brokered cease-fire.
The northern city of Aleppo, Syria's largest and its former commercial center, has seen particularly fierce fighting, as pro-government forces try to capture neighborhoods in besieged opposition-held parts of the city.
The activist-operated Aleppo Today TV station and Qasioun news agency said bunker-busting bombs were used in an attack on the Bustan al-Qasr neighborhood in rebel-held eastern Aleppo.
Zakaria Amino, a member of the Aleppo local council, said bombs fell on a number of other rebel-held neighborhoods.
The opposition-held part of Aleppo has been battered by an intensive aerial campaign since last month, when the truce collapsed after just a week. Syrian pro-government forces also are conducting a ground offensive into the rebel-held districts, advancing slowly in the north, east and south of the city.
The Britain-based Syrian Observatory for Human Rights said the airstrikes on Aleppo killed at least 16 people, while the Local Coordination Committees said 14 were killed.
In the southern city of Daraa, where the conflict began after anti-government protests in March 2011, rebels fired rockets at government-held areas. One hit a primary school, killing six people -- among them five children -- and wounding 18 students, according to the Syrian Arab News Agency. It said some of the wounded are in serious condition.
The new agency posted a photo of a boy carried on a stretcher, his gray trousers stained with blood and his bandaged right hand on his stomach. Another photo showed a boy and a girl inside what appeared to be a hospital with intravenous drips in their arms.
Blame for Russia
Several participants are mired in Syria's civil war, including the U.S., which has backed moderate rebel groups and an airstrike campaign against the Islamic State, and Russia, which has bolstered the forces of Syrian President Bashar Assad with its own airstrikes against groups it defines as terrorists.
But British Foreign Secretary Boris Johnson said Tuesday that "all the available evidence" points to Russian responsibility for the bombing of an aid convoy in Syria.
Johnson told the House of Commons that Russia is "in danger of becoming a pariah nation," and said he would like to see protests outside the Russian Embassy against Russia's military actions in Syria.
But he did not mention any new action against Russia, signaling he does not back calls from several lawmakers for a no-fly zone to be enforced over Syria.
"We cannot do that unless we are prepared to shoot down planes or helicopters that violate that zone, and we need to think very carefully about the consequences," Johnson said.
Johnson said "our best hope is to persuade the Russians" to "do the right thing" and back a genuine cease-fire.
Britain's air force is part of a U.S.-led coalition attacking Islamic State militants in Syria, but in 2013 lawmakers rejected a government plan for airstrikes against Assad's forces.
The Russian Embassy in London responded to Johnson's comments in a tweet, saying Russia's "record on Syria is thousands of freed villages, thousands of tons of humanitarian aid. What's Britain's?"
Separately, Russian President Vladimir Putin canceled a visit to Paris after French President Francois Hollande called the recent bombings of Aleppo a "war crime" and questioned publicly whether it made sense to meet with Putin at all.
French officials have said that they want the International Criminal Court's prosecutor to open a war-crimes investigation into Russia and Syria's airstrikes in Aleppo.
Russia said it is targeting only terrorists in Aleppo, and has accused the West of using so-called terrorist groups to seek the downfall of Assad.
The Kremlin confirmed that next week's planned visit to Paris had been canceled, ostensibly because the opening of a Russian cultural and spiritual center had been delayed. But the presidential spokesman, Dmitri Peskov, also noted that "Putin said that he would be ready to visit Paris when it was convenient" for Hollande.
The United States last week halted diplomatic talks with Russia because of the Aleppo bombing, claiming Russia had "failed to live up to its own commitments." Russia on Saturday blocked a French-sponsored U.N. Security Council resolution that would have imposed a no-fly zone in Syria. A Russian counterproposal, also vetoed, would not have halted airstrikes in Aleppo.
Hollande on Sunday had questioned whether he should receive Putin at all.
"I asked myself the question: Is it useful? Is it necessary? Can it be a way of exerting pressure? Can we get him to stop what he is doing with the Syrian regime?" he said during an interview on France's TMC television channel.
Information for this article was contributed by Jill Lawless and staff members of The Associated Press and by Andrew Roth of The Washington Post.
A Section on 10/12/2016