The Syrian authorities have made several arrests related to the murder of a senior military adviser to Bashar al-Assad, the president, Arab media reported yesterday.

Although neither Syria's official nor privately owned media have mentioned the case, reports of the assassination of General Mohammed Suleiman have led to speculation about internal divisions in Syria's ruling circle.

Gen Suleiman was killed by sniper fire in the port city of Tartous on Friday, several Arab media have said.

There is no confirmation from Syria on the position that Gen Suleiman held but it is claimed he was the government's liaison with Lebanon's Hizbollah movement, the militant group closely allied with Damascus and Tehran which waged a war with Israel in 2006. A Hizbollah spokesman in Lebanon has said the group was not familiar with Gen Suleiman.

The killing comes six months after the assassination in Damascus of Imad Moughniyeh, a senior Hizbollah commander. Hizbollah has accused Israel of the bomb attack in which he died but the office of Ehud Olmert, the prime minister, issued a denial at the time. Israel has now also denied "any direct knowledge" of the killing of Gen Suleiman.

Syria has yet to report on its investigation into Moughniyeh's killing. In the wake of his death, Syrian opposition figures talked of splits within the country's security services. The killing of Gen Suleiman has rekindled the speculation.

Syria and Israel earlier this year disclosed they were holding peace talks under Turkish mediation. President Assad visited Ankara yesterday, in the wake of a visit to Iran, and peace talks were expected to be on the agenda. In Iran, Mr Assad tried to propose Syria as a mediator in that country's nuclear dispute with the international community.