Some 182 civilians have been killed since US-backed, Kurdish-led forces launched an offensive to seize the strategic northern Syrian city of Minbij from Islamic State jihadists at the end of May, a monitoring group said on Sunday.

The victims included 56 children, the Syrian Observatory for Human Rights said. Some 64 of them, including 22 children, died in airstrikes by a US-led coalition.

The Kurdish-led Democratic Forces of Syria (DFS) launched an offensive against Minbij, which lies about 30 kilometres from the Turkish border, on May 31 backed by intensive coalition airstrikes.

Capturing the city and its hinterland would cut Islamic State off from its last access route to the border and the outside world.

The DFS quickly surrounded Minbij but have made slow progress since then, with Islamic State jihadists fiercely resisting in street fighting inside the city.

According to analysis firm IHS, in a report also released on Sunday, the fall of Minbij would have a major impact on Islamic State's ability to bring supplies and fighters to its de facto Syrian capital of al-Raqqa and its remaining territories in Syria and Iraq.

Meanwhile, the Observatory said that 29 rebel and al-Qaeda fighters, including field commanders, had been killed in fierce battles as they attempted to force government troops back from the last road into rebel-held eastern Aleppo.

Government forces cut off the Castello Road on Thursday, effectively imposing a siege on the estimated 250,000 to 300,000 residents remaining in the divided city's bomb-shattered eastern sector.

Also on Sunday, the World Food Programme announced that it had airlifted 40 tons of food to the mostly Kurdish-held north-east of Syria.

A total of 25 flights are planned over the coming month, prioritizing supplies for displaced people in shelters and unfinished buildings, female-headed households and some vulnerable Iraqi refugees, the UN agency said.

Syria's north-eastern al-Hassakeh province has been inaccessible for aid agencies as land routes within the country are controlled by Islamic State and the Turkish and Iraqi borders have been largely shut in recent months.

Aid deliveries have been a contentious issue in the Syrian war, with the government frequently preventing or restricting convoys to rebel-held areas besieged by its forces despite widespread malnutrition and some cases of death by starvation.

Three besieged areas on the outskirts of Damascus have received aid supplies, for the first time since 2012, after an international deadline for relief provisions expired at the beginning of June.

The United States, Russia - an ally of the Syrian government - and other countries had jointly announced that if humanitarian aid was denied to besieged areas from June 1, WFP would pursue air drops.

The UN, however, subsequently made it clear that it was still focussing on getting approval for overland deliveries, saying airlifts would be technically difficult and could not be carried out without government approval.

The Syrian conflict, which began with peaceful protests against al-Assad's regime, has turned into a four-way war between the government, mainly Islamist rebels, the Islamic State extremist group and leftist Kurdish forces.

Some 4.8 million Syrians have fled the country since 2011, with another 6.6 million displaced inside its borders, according to the latest UN estimates.

Latest news

New Zealand PM: We need migrants as 'locals can't pass drug tests'

New Zealand Prime Minister Bill English said Monday his country has to rely on immigrant workers because many locals can't pass workplace drug tests.

No early parliamentary election in Serbia this year - media

There will be no early parliamentary election in Serbia this year, electronic media in Belgrade said on Sunday.

Full list of 2017 Oscar winners

A list of winners at the 89th Academy Awards:

"Moonlight" wins best picture after on-stage Oscars mixup

The coming-of-age drama about an African American boy growing up gay in a poor neighbourhood in Miami was made for just 1.5 million dollars. Its director and co-writer, Barry Jenkins, hadn't made a film in years. And it was up for the best picture prize against "La La Land," the smash hit musical that tied the record for Oscar nominations this year.

Emma Stone is best actress in winning night for 'La La Land'

Emma Stone won the best actress Oscar at the 89th Academy Awards for her role in the movie musical "La La Land" on Sunday.

Casey Affleck wins best actor at Oscars

Casey Affleck won the best actor trophy at the Oscars in Los Angeles on Sunday for his portrayal of a taciturn janitor with a troubled past in "Manchester by the Sea."

Thousands of Romanians revive anti-government protests

Thousands of Romanians turned out on Sunday to renew their demands for the government to step down amid accusations it is trying to protect corrupt politicians.

Francis, first pope to visit Anglicans in Rome, weighs S Sudan trip

Pope Francis became the first leader of the Catholic Church to visit the Anglican community in Rome on Sunday, where he said he was considering a trip to famine-struck South Sudan.

Ibrahimovic lifts Man United past Southampton in League Cup final

Zlatan Ibrahimovic scored an 87th-minute winner as Manchester United beat Southampton 3-2 in an exciting League Cup final on Sunday.

London screens Iranian director's film amid Oscars boycott

Thousands of people watched a free screeening of Iranian director Asghar Farhadi's film "The Salesman" in London on Sunday to coincide with the Oscars.

Real Madrid stage comeback to stay top; Messi scores in Barcelona win

Lionel Messi scored the winner as Barcelona beat Atletico Madrid 2-1 on Sunday to move top of the Spanish first division.

Dubrovnik Sun Gardens Hotel member of The Leading Hotels of the World

The Dubrovnik Sun Gardens Hotel has joined the Leading Hotels of the World, Ltd., a global hospitality consortium of more than 375 hotels and resorts in over 75 countries.