A senior Syrian intelligence chief has been killed by rebel forces in the eastern province of Deir al-Zour, the opposition and Syrian state media said Thursday, as the rebels claimed new gains in the region.

Gen. Jameh Jameh, who led the Syrian military intelligence unit in the province, died “carrying out his mission in defending Syria,” state television said in a report. It gave no details, but Lt. Col. Mohammad Abboud, a top rebel commander for the eastern front, said Jameh, 59, was fatally shot near his home in the al-Joura neighborhood of Deir al-Zour city, the provincial capital.

The Britain-based Syrian Observatory for Human Rights said rebel snipers shot Jameh in the midst of a battle.

Jameh, one of Syria’s most powerful generals, was frequently linked to the 2005 car-bomb assassination of Rafiq al-Hariri, a former Lebanese prime minister and an outspoken critic of the Syrian army’s presence in his country. Jameh, who was based in Beirut at the time, was questioned by U.N. investigators in relation to the assassination.

On his return to Syria, he was appointed chief of Syrian military intelligence in Deir al-Zour and soon gained a fearsome reputation.

“General Jameh Jameh has been a household name of terror in the province even before the uprising,” said Hassan Hassan, a Syria analyst and columnist for the Abu Dhabi-based National newspaper and a native of the province. “After the uprising, he was even more brutal, running an intricate web of informants and agents. People across Deir al-Zour are celebrating his death.”

In 2011, the European Union imposed sanctions on Jameh, saying he had been “directly involved in violence against the civilian population” of Deir al-Zour.

Although the war has been reduced to a grinding stalemate on many front lines in recent months, and the rebels have been distracted by side battles against jihadists and Kurds, the opposition says it is making progress against the government in the eastern province with an operation known as “One Body.”

Abboud said rebel forces, including al-Qaeda-linked Jabhat al-
Nusra, have launched a fresh assault to take control of strategic government footholds in the province over the past three days. He claimed gains near the Deir al-Zour military airport, with heavy clashes on Thursday night.

Efforts to bring both sides to the negotiating table in Geneva have been repeatedly delayed. On Thursday, for the first time, the Syrian government floated a potential date for the summit. Speaking in Moscow, Syrian Deputy Prime Minister Qadri Jamil said the meeting was “closer than ever” and would be held Nov. 23 and 24, according to comments carried by the Russian news agency RIA Novosti.