Syria's military backed by Russian warplanes have killed more than 150 people in eastern Aleppo this week say rescue workers, part of a renewed bombardment supporting an offensive to seize the city's shattered rebel-held sector.

 

As air strikes and shelling of the city's east intensified since Tuesday after a brief period of relative calm, Syria's government approved a U.N. plan to allow aid convoys into most besieged areas of Syria, with the exception of Aleppo.

 

Rising casualties in Aleppo, where buildings have been reduced to rubble or are lacking roofs or walls, have caused international outcry and a renewed diplomatic push, with talks between the United States and Russia planned for Saturday.

 

Now in its sixth year, Syria's civil war has killed 300,000 people and made millions homeless while dragging in regional and global powers and inspiring jihadist attacks abroad.

 

President Bashar al-Assad is backed by Russia's air force, Iran's Revolutionary Guards and an array of Shi'ite militias from Arab neighbors, while Sunni rebels seeking to oust him are backed by Turkey, the United States and Gulf monarchies.

 

Air strikes killed 13 people on Thursday in the rebel-held Aleppo districts of al-Kalaseh, Bustan al-Qasr and al-Sakhour according to a civil defense official, while European Union foreign ministers drafted a statement accusing Syria and its allies of violence that "may amount to war crimes".

 

"Since the beginning of the offensive by the (Syrian) regime and its allies, the intensity and scale of aerial bombardment of eastern Aleppo is clearly disproportionate," a draft of their statement seen by Reuters said.

 

Syrian military officials could not immediately be reached for comment on the latest situation in Aleppo. The Syrian and Russian governments say they only target militants.

 

OBAMA TO REVIEW OPTIONS

 

U.S. President Barack Obama and his senior foreign policy advisers are expected to meet on Friday to consider military and other options in Syria, U.S. officials said.

 

Some officials argue the United States must act more forcefully in Syria or risk losing what influence it still has over moderate rebels and its Arab, Kurdish and Turkish allies in the fight against Islamic State, the officials told Reuters.

 

U.S. officials said they consider it unlikely that Obama will order U.S. air strikes on Syrian government targets, and they stressed that he may not make any decisions at the planned meeting of his National Security Council.

 

U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov are due to meet in Switzerland on Saturday to resume their failed effort to find a diplomatic solution along with counterparts from some Middle East states.

 

Moscow on Thursday called on regional states not to supply portable anti-aircraft missiles to Syrian rebel groups, warning that any unfriendly actions against Russian forces would elicit an appropriate response.

 

Speaking to a Russian newspaper, Syria's Assad said his country's only hope was that Moscow could convince Turkey to end its support of the rebellion, a move that would cut insurgents off from their main external supply route.

 

"IT'S GOING ON NOW"

 

Air strikes against rebel-held areas of eastern Aleppo had tapered off over the weekend after the Syrian army announced it would reduce raids for what it described as humanitarian reasons, but they have intensified since Tuesday.

 

"The bombing started at 2 a.m. and it's going on until now," Ibrahim Abu Laith, an official at the civil defense rescue organization in Aleppo, told Reuters from Aleppo. Rescue workers said 154 people had been killed in recent days. Reuters could not independently verify the death toll.

 

Aleppo has been divided between government- and rebel-controlled areas for years. More than 250,000 people are believed to be trapped in eastern Aleppo, the rebels' most important urban stronghold, facing shortages of food, fuel and medicine.

 

In Geneva, the United Nations said Damascus had partially approved its aid plan for October, giving the green light for convoys to 25 of 29 besieged and hard-to-reach areas across Syria, which are also deprived of some vital supplies.

 

However, the Syrian government did not give approval for either eastern Aleppo or three districts near Damascus, Ramzy Ezzeldin Ramzy, the United Nation's deputy special envoy to Syria said on Thursday, describing the situation as "dire".

 

The war has badly affected government-held regions of Syria too and on Thursday Damascus and Moscow struck a deal to import one million tonnes of Russian wheat, enough to cover the needs of those areas for a year, at cheap prices.

 

In a government-held area of western Aleppo, at least four children were killed and 10 wounded on Thursday when shells landed near a school, the Syrian Observatory for Human Rights reported.

 

Syrian state news agency SANA said the school in the al-Suleimaniya area had been targeted in what it described as a terrorist attack.

 

The Observatory, a Britain-based war monitoring group, also said shelling on government-held parts of Aleppo had killed eight people on Wednesday and said 79 civilians had been killed in eastern Aleppo since Tuesday.