GENEVA (Reuters) - The Syrian opposition delegation at peace talks in Geneva is aiming for the removal of President Bashar al-Assad and plans to engage his negotiators in serious and direct talks, the head of the opposition delegation Nasr Hariri said on Monday.

Nasr al-Hariri, Head of the Syrian High Negotiations Committee (HNC), leaves after a news conference before the opening of Intra Syria talks in Geneva, Switzerland November 27, 2017. REUTERS/Denis Balibouse

Hariri called for major powers, especially Russia, to pressure the Assad government into real negotiations on a political transition followed by a new constitution and free elections, in line with a U.N. roadmap to end the six-year war.

“We stress that political transition which achieves the ousting of Assad at the beginning is our goal,” Hariri told a news conference after arriving in Geneva for a round of U.N.-led talks that is scheduled to start on Tuesday.

“Our goal in the negotiation will be the departure of Bashar al-Assad from the beginning of the transition,” he said.

A breakthrough in U.N.-backed Syria peace talks in Geneva this week seems hardly more likely than in seven failed earlier rounds as Assad pushes for total military victory and his opponents stick by their demand he leave power.

All previous diplomatic initiatives have swiftly collapsed over the opposition demand that Assad must go and his refusal to do so.

The Syrian government delegation, led by its U.N. ambassador and chief negotiator Bashar al-Ja’afari, failed to arrive in Geneva on Monday when it had been due. It was not clear whether the delegation would arrive on Tuesday, when U.N. mediator Staffan de Mistura is due to meet the opposition.

“We don’t have high hopes, the regime is using delaying tactics to obstruct progress toward a political solution, at a time when the opposition comes with one unified delegation,” Hariri said. “Russia .. .is the only entity capable of bringing the regime to the table of negotiations.”

For many years, Western and Arab countries backed the opposition demand that Assad leave office. However, since Russia joined the war on behalf of Assad’s government two years ago it has become increasingly clear that Assad’s opponents have no path to victory on the battlefield.

The Syrian civil war, now in its seventh year, has killed hundreds of thousands of people and caused the world’s worst refugee crisis, driving 11 million from their homes.

The Syrian government continued its bombing and sieges of areas including 400,000 people in eastern Ghouta, a rebel-held Damascus suburb, Hariri said on Monday.

“We are here for the hundreds of thousands who under siege who are in grave need of humanitarian aid and for hundreds of thousands of detainees who are at the verge of death, suffering but living death every day,” he said.