A high-level Syrian general has been killed during a battle with rebels in the eastern province of Deir Ezzor, according to state media.
Major-General Jameh Jameh was head of military intelligence in the province, where the regime has been battling armed opposition fighters seeking to overthrow President Bashar al-Assad.
"Major-General Jameh Jameh was martyred while carrying out his national duties to defend Syria and its people and pursuing terrorists in Deir Ezzor," state television said on Thursday.
State media gave no immediate details on when, where in the province Jameh was killed, or how, but rebels forums said he died during clashes with fighters in the city of Deir Ezzor.
Rami Abdel Rahman, director of the UK-based Syrian Observatory for Human Rights, said initial reports suggested Jameh had been shot by a sniper in the city's Rashdiya district, but there was no confirmation.
In-depth coverage of escalating violence across Syria
The group also reported fierce fighting between regime troops and rebels in several parts of the province, including the city, which is the largest in eastern Syria.
Jameh was one of Syria's senior security officers in Lebanon during Syria's military deployment in the country between 1976 and 2005.
He was interrogated over the February 2005 assassination of Rafiq Hariri, the Lebanese politician, though he was not charged in connection with his death.
Many blamed the Beirut car bombing that killed Hariri on Assad's government and the Lebanese group Hezbollah, which is allied to Assad and is now fighting alongside him in Syria against the rebels.
In 2006, the US Treasury Department announced it was blacklisting Jameh and another Syrian general for their role in supporting "terrorist groups" and over the presence in Lebanon.
He is believed to be from Jableh, a town in coastal Latakia province, a stronghold of the Syrian regime.
In Thursday's other Syria-related developments, the Organisation for the Prohibition of Chemical Weapons (OPCW), which was awarded the Nobel Peace Prize last week, said nearly half its inspections of the arsenal were complete.
"We have done nearly 50 percent of the verification work of the facilities that have been declared to us," Malik Ellahi, a political adviser on Syria for OPCW, said in The Hague.
Despite the progress, Ellahi said security remained a concern for the mission in Syria, with mortar and car bomb attacks taking place in areas near to the inspectors' Damascus hotel.
"There have been a number of incidents over the last few days which gives some cause for concern," Ellahi said.
So far Syria has won praise for its cooperation with the inspectors, but the UNs has stressed that crucial deadlines be met.
These include verifying Syria's disclosed chemical weapons, identifying key equipment, destroying production facilities and starting the destruction of Category 3 chemical weapons by November 1.
Inspectors have until June 30 next year to complete the destruction of Syria's chemical arsenal.
Earlier on Thursday, Qadri Jamil, Syrian deputy prime minister, said in Moscow that a proposed peace conference in thte Swiss city of Geneva could take place November 23-24, saying "we are closer than ever to holding the Geneva 2".
The peace process will get a renewed push from John Kerry, the US secretary of state , who will travel to London next week for a meeting of the core countries making up the Friends of Syria, the State Department said on Thursday.
Kerry said "we are trying to move the process forward. I'll have meetings next Tuesday in London with the support group of the [Syrian] opposition".
"We're working towards this Geneva conference, not that we know what the outcome is," he said in an US radio interview.
Syria's conflict began two and a half years ago as protests against four decades of Assad family rule that degenerated into a bloody civil war. More than 100,000 people have died in the violence.