The U.N. said Wednesday it is using newly opened land routes in Syria to expand food deliveries to areas around the northern city of Raqqa, where U.S.-backed forces are battling Islamic State militants in their self-declared capital.

The new access has allowed the World Food Program to deliver food to rural areas north of the city for the first time in three years.

More than 190,000 people have been displaced from and within Raqqa province since April 1, according to the U.N. refugee agency. In the past 48 hours, hundreds of civilians managed to flee areas under IS control and cross to territory seized by the U.S.-backed fighting force known as the Syrian Democratic Forces, according to the Syrian Observatory for Human Rights.

As the map of control changes, so is the access and WFP said it is now delivering food every month to nearly 200,000 people in eight hard-to-reach locations inside Raqqa province as well as other areas in a neighboring province.

Prior to the re-opening of the road linking Aleppo in the west to Hasakeh in the east, the WFP relied on airlifts.

"Replacing airlifts with road deliveries will save an estimated US$19 million per year, as each truck on the road carries the equivalent of a planeload of food at a significantly lower cost," said Jakob Kern, the WFP country representative in Syria.

"With these cost savings and improved access, we are now reaching more families and people returning to their homes who need our help with regular food deliveries."

One area that is now reachable is the town of Tabqa, which was taken from IS by the U.S.-backed Syrian Democratic Forces in May. WFP said it was able this month to double the number of people it reaches, delivering monthly food rations to 25,000 people, many of whom have returned to their original homes and are now working to rebuild their lives.

The advance toward Raqqa city began last year, with the SDF fighting to clear rural parts around the city. Backed by airstrikes from the international coalition, the Syrian fighters captured the strategic town of Tabqa and a major nearby dam in May.

The fight against the Islamic State group is only one facet of the war in Syria, which is now in its seventh year. Six rounds of U.N.-brokered peace talks in Geneva have failed to bring the warring sides closer to a political settlement.

A seventh round is now underway in the Swiss city, but expectations for a breakthrough are almost non-existent.

On Wednesday, the head of the Syrian opposition delegation accused President Bashar Assad's government of refusing to engage in political discussions.

Nasr al-Hariri of the High Negotiations Committee also challenged the U.N. Security Council to "uphold its responsibilities" and maintain pressure on Assad to honor resolutions that the council has passed. He spoke to reporters after emerging from talks with the U.N. envoy for Syria, Staffan de Mistura, in the latest round of indirect peace talks.

Al-Hariri cited the "continuous refusing" of Assad's government to participate in political negotiations.

Security Council resolution 2254 from December 2015 called on top U.N. officials to convene the two sides "to engage in formal negotiations on a political transition process."

Also Wednesday, a human rights group said Syrian-Russian airstrikes and artillery attacks on a town in southern Syria last month killed 10 civilians in and near a school.

Human Rights Watch said one of the airstrikes hit the courtyard of a middle school in the town of Tafas in the southern province of Daraa, killing eight people, including a child. It says most of those killed were members of a family who had been displaced from another town.

It said two other civilians, including a child, were killed an hour earlier by artillery attacks near the school.

Bill Van Esveld, senior children's rights researcher at the U.S.-based Human Rights Watch, said Wednesday that "as long as no one is held responsible for such repeated unlawful attacks, it's likely they will continue."