BEIRUT (Reuters) - Syrian pro-government forces recaptured a key rebel-held town in coastal Latakia province on Sunday, building on battlefield advances in the area ahead of planned peace talks this week in Geneva between Damascus and Syria’s opposition.

Government troops and militiamen, supported by Moscow’s air power and joined on the ground by Lebanese Hezbollah fighters and Iranian forces, have pressed offensives in the west and northwest of the country in recent months, seeking to reverse gains made by insurgents last year.

The latest advance comes ahead of peace talks originally set for Monday but which now look likely to be delayed, partly due to a dispute over the opposition negotiating team’s composition. The opposition has also said Russia must stop bombing civilian areas and Damascus must lift sieges before it will join talks.

The recapture of the town of Rabiya in Latakia province has paved the way for an advance up to the border with Turkey, the Britain-based Syrian Observatory for Human Rights said. Syrian state television confirmed Rabiya’s capture.

Turkey supports insurgents battling the forces of President Bashar al-Assad, who has the backing of Russia and Iran.

The Observatory described Rabiya as the “second most important base for (rebel) fighters in the northern Latakia countryside” after the town of Salma, which pro-government forces seized earlier this month in one of the most significant advances since Russia joined the fight.

TALKS DEADLINE APPROACHING

The United States has said it is confident the talks in Geneva will go ahead this week despite continued disagreements.

Lead opposition negotiator Mohamad Alloush said Kerry had put pressure on them to attend the Geneva talks in order to negotiate a halt to Russian bombardments, the lifting of blockades and the release of detainees - measures it has insisted must be implemented before any negotiations go ahead.

“Kerry came to pressure us to give up our humanitarian rights,” Alloush, a politburo member of rebel group Jaysh al-Islam (Islam Army), told Reuters.

“There will be a big response to these pressures,” he told Reuters, without elaborating.

Asked about the chances of negotiations going ahead, he said: “We leave this to the coming hours.”

Earlier a Western diplomat said talks would be unlikely to begin before Wednesday, with the opposition negotiating team formed after a conference in Saudi Arabia last month taking stock in Riyadh until Tuesday.

The United Nations has said it would not issue invitations to talks until major powers reach agreement on which rebel representatives should attend. U.N. envoy Staffan de Mistura had been expected to issue invitations on Sunday.

Syrian armed rebel groups said on Saturday they held the Syrian government and Russia responsible for any failure of talks.

U.S. Vice President Joe Biden said on Saturday the United States and Turkey were prepared for a military solution against Islamic State in Syria should the Syrian government and rebels fail to reach a political settlement.

Washington is waging an air campaign against the jihadists in areas they control in northern and eastern Syria.

Russia is separately striking Islamic State, including in Deir al-Zor province, where the Syrian Observatory said on Sunday raids believed to be carried out by Russian jets killed 63 people.

The Syrian conflict, which began in 2011, has killed an estimated 250,000 people and displaced a further 11 million.