The Islamic State jihadist group has executed more than 90 people, a third of them civilians, over the past month in areas of war-torn Syria under its control, a monitoring group said Sunday.

The Syrian Observatory for Human Rights said 32 civilians were among 91 people executed for "crimes" in the jihadist group's self-proclaimed caliphate between July 29 and August 29.

Tajikistan on Saturday accused the country's beleaguered Islamic party of ties with the Islamic State group based mainly in Iraq and Syria.

Members of the Islamic Renaissance Party of Tajikistan (IRPT) have been "in active contact with militants in Syria" and have responded to the militants request to "raise the black flag of IS," an interior ministry spokesman said. 

Turkish warplanes have for the first time joined raids by the U.S.-led coalition against Islamic State positions in Syria, the foreign ministry said Saturday, after Washington urged Ankara to play a full role in the battle against the jihadists.

"Our fighter planes ... along with planes from the coalition yesterday (Friday) evening began joint operations against (IS) targets which pose a threat to the security of our country," the Turkish foreign ministry said in a statement.

Lebanon should form a "national commission on disappearances" to investigate those still missing since the country's civil war, a rights group said Saturday. 

On the eve of the U.N.'s International Day of the Disappeared, Human Rights Watch also called on Lebanon to prosecute recent cases of enforced disappearances on its territory and ratify the U.N.'s relevant convention.

Rescuers have retrieved from the sea the bodies of 111 migrants whose boat sank off the coat of Libya, the Red Crescent said on Saturday in a new toll.

A spokesman for the Libyan relief organisation said dozens are still missing after Thursday's tragedy.

A brief truce between Syrian regime forces and rebel groups in three key towns ended early Saturday as the warring parties resumed clashes and shelling, a monitoring group and a mediator said.

Pro-regime forces, including Hizbullah, had agreed on a 48-hour ceasefire, until dawn on Saturday, in the rebel bastion of Zabadani and the government-held villages of Fuaa and Kafraya. 

Ministerial sources following up closely on the contacts between political factions said they are waiting for the initiative expected to be kicked off by Speaker Nabih Berri to hold consultations to bring the rival politicians on the dialogue table either in Ain el-Tineh or in parliament.

The Speaker is thoroughly studying the initiative and has not failed to test the waters, exploring the reactions in advance, the sources told al-Joumhouria daily on Saturday.

Syria's four-and-a-half year conflict has driven half of the country's people to flee their homes, with the number of those who have left the country approaching 20 percent of the pre-war population.

At least 7.6 million people are displaced within Syria, which counted 23 million inhabitants at the start of the civil war.

A tech-savvy U.S. teenager from Virginia was sentenced to 11 years and four months in prison on Friday for conspiring to provide material support to the Islamic State extremist group.

Ali Shukri Amin, 17, from the small town of Manassas an hour's drive from Washington DC, will be subject to a lifetime of supervised release and monitoring of his Internet activities.

Russia on Friday hosted the newly appointed U.S. special envoy for Syria as world powers intensify efforts to end the four-year civil war raging in the country.

The new envoy, Michael Ratney, who was appointed to his position last month, had previously worked for the State Department in the Middle East.