A Jesuit priest who vanished in northern Syria and was feared dead at the hands of an al-Qaida offshoot might be alive, a prominent activist group said after backtracking on an earlier report.

The UK-based Syrian Observatory for Human Rights (SOHR) said Father Paolo Dall'Oglio could have been taken to an undisclosed location by members of jihadist group the Islamic State of Iraq and Levante (ISIS), in order to hold talks with group leader Abu Bakr al-Baghdadi.

Last week SOHR cited local activists as saying Dall'Oglio had been killed in the Isis prison in ar-Raqqah.

The Rome native, 58, vanished in the rebel-held northern city on 29 July.

He had voluntarily approached ISIS at their headquarters to negotiate the release of a group of hostages and broker a truce between different rebel factions locked in a struggle for control of the city.

Isis's grip over ar-Raqqah has fuelled tension and deadly clashes between the Islamist group, Kurdish factions and moderate rebel groups such as the Ahfad al-Rasul brigade.

A rebranding of al-Qaida's Iraqi branch, Isis is mostly made up of non-Syrian Islamists, and its brutal methods and Islamist agenda are unpopular with locals.

Al-Baghdadi, also known as Abu Dua, is listed as a specially designated global terrorist by the US, which has also put up a $10m (£6.3m) reward for information leading to his capture or death.

Dall'Oglio had been a Jesuit missionary to Syria since the early 1980s and was reportedly loved by the local population.

He had worked to rebuild a ruined ancient monastery and turn it into a centre devoted to Muslim-Christian friendship.

Unlike representatives of other Christian minorities in Syria, who sided with Assad fearing an Islamist takeover, the clergyman urged the Vatican to back the rebellion.

He was expelled from the country by the regime in June 2012 but re-entered in January.

Protesters have been demonstrating almost every day outside the ISIS headquarters in ar-Raqqah, demanding his and other prisoners' release.

No request for a ransom or hostage exchange has been made by the clergyman's kidnappers.

Counter-terrorism experts told IBTimes UK that such a modus operandi is unusual for a jihadist group, but might be due to the presence of members of a hardline strand of Islam known as the Takfiri among Isis ranks.