Rebels make major breakthrough in Syria with Aleppo siege

BEIRUT - Rebels say they have breached the siege imposed by the Syrian government on opposition neighborhoods in the northern city of Aleppo, in a major military breakthrough after intense fighting.

The Syrian government seized the only route into rebel-held areas in northern Aleppo last month, prompting a rebel counteroffensive from the city's south. The U.N. said 300,000 people were trapped, making Aleppo one of the largest besieged areas in Syria.

A broad coalition of rebel groups posted videos Sunday of fighters roaming the Ramouseh district, where the siege was breached following overnight clashes. The district houses a number of military colleges.

The war media arm of Lebanon's Hezbollah, the group fighting alongside the Syrian government, conceded the rebels' advance, adding that airstrikes leveled one of the military colleges after forces withdrew.

In Geneva, the U.N. envoy for Syria has said he aims to call a new round of talks between government and opposition envoys in Geneva "toward the end of August."

Staffan de Mistura said he wants to see the outcome of steps agreed upon in Moscow between the United States and Russia, in order "to make these talks particularly fruitful and hopeful" before setting a precise date.

Syrian government forces and their allies have been on the offensive around the Aleppo, Syria's largest city and former commercial center, for weeks.

Last week a Russian transport helicopter was shot down near Aleppo, killing all five aboard.

The Mi-8 helicopter was shot down in Idlib province while returning to the Russian air base on Syria's coast after delivering humanitarian goods to the city of Aleppo, the Russian government said in a statement.

However, a Syrian rescue service told the Reuters news agency that toxic gas was dropped on a Syrian town near where the Russian helicopter was shot down.

Syria Civil Defence, which describes itself as neutral group of search and rescue volunteers, posted a video online which purportedly shows men, struggling to breathe, being given oxygen by people wearing the group's uniform, Reuters said.

The helicopter had three crew members and two officers deployed with the Russian center at the Hemeimeem air base on the Syrian coast.