Syrian troops backed by Russian air strikes have advanced against fighters in the centre of the country as Russian President Vladimir Putin defended Moscow's intervention in the conflict, saying it would aid efforts to reach a political settlement.
Putin said his country's objective was to stabilise the Syrian government and create conditions for a political compromise.
"When a division of international terrorists stands near the capital, then there is probably little desire for the Syrian government to negotiate, most likely feeling itself under siege in its own capital," he said in an interview with Russian state television broadcast on Sunday.
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He also called on other countries to "unite efforts against this evil [terrorism]".
Critics of Russia's intervention have argued that strengthening the government will make reaching a compromise more difficult, and on Sunday the main Western-backed opposition group said the strikes would undermine efforts to reach a settlement.
The Syrian National Coalition also said it would boycott talks suggested by the UN envoy for Syria, Staffan de Mistura, saying any political process must be based on "ending the Russian aggression" and reviving a plan adopted in 2012.
Fighting in Hama
Fighting on Sunday was on multiple fronts in the northern part of the central Hama province and the nearby rebel-held Idlib province.
A Syrian military official, speaking on condition of anonymity in line with regulations, told the AP news agency that troops have seized the northern Hama village of Tak Sukayk.
The Syrian Observatory for Human Rights said regime troops and fighters from the allied Lebanese Shia militia Hezbollah recaptured the town of al-Bahsa in Sahel al-Ghab in the northwest of Hama.
The reported advance comes a day after Syrian troops, backed by a Russian air cover, retook two other strategic towns in Sahel al-Ghab, where the Islamic State of Iraq and the Levant (ISIL) group was not known to have presence.
Russia says its air strikes are mainly aimed at ISIL fighters and other "terrorists," but its ground-and-air offensive is being waged in areas controlled by "moderate" rebels as well as al-Nusra Front.
US officials say Russia has directed parts of its air campaign against US-funded groups and other moderate opposition groups in a concerted effort to weaken them.
Shaam News Network, a group of anti-government activists, said on Sunday that several rebel groups, including al-Nusra Front, have formed a joint operations room for activities in Hama and Idlib.
The rebels seized almost all of Idlib earlier this year and hold territory in northern Hama and rural Latakia, a coastal province that is a major stronghold for President Bashar al-Assad and the Alawite religious minority to which he belongs.
Human Rights Watch, meanwhile, said that an advanced type of Russian cluster munition was used in an air strike southwest of Aleppo on October 4, as part of what photographs and videos suggest is renewed use of the air-dropped and ground-fired munitions.
The New York-based rights group said it could not determine whether Russian or Syrian forces were responsible for the apparent use of the weapons, which descend by parachute and are designed to destroy armoured vehicles, but can also pose a major hazard to civilians.
Russia is a major arms supplier to Syria. Neither country has banned cluster munitions.
There was no immediate comment from Russia's defence ministry.
The Russian military said on Sunday its jets had carried out 64 sorties in the past day, targeting 63 sites in the Hama, Idlib, Latakia and Raqqa provinces.
On Sunday, Putin met Prince Mohammed bin Salman, Saudi Arabia's defence minister, about the possibility of a political solution in Syria.
The two held talks in Sochi and were joined by Sergey Lavrov, Russia's foreign minister, and Alexander Novak, energy minister.
"We have closely cooperated with Saudi Arabia for years on the crisis in Syria," Lavrov said, according to remarks broadcast on television.
"The two parties confirmed that Saudi Arabia and Russia have similar objectives when it comes to Syria. Above all, it is to not let a terrorist caliphate take over the country."
"After today's talks, we understand better how to move towards a political solution," Lavrov said.
Riyadh is one of the leading backers of rebels fighting to overthrow Assad.
Putin also met Abu Dhabi's crown prince the southern Russian city, where they attended a Formula One race.