May was the bloodiest month so far this year in Syria, with at least 6,657 people killed throughout the war-ravaged country, a monitor said Monday.

According to the Syrian Observatory for Human Rights, the toll includes at least 1,285 civilians, more than half of whom were killed in regime air raids.

Syria's parliament speaker on Monday paid tribute to Iran for its "effective role" in helping his embattled government overcome sanctions and fight an armed rebellion.

Jihad al-Lahham made the remarks during a visit to Tehran, the Damascus regime's main regional ally which provides the government of President Bashar Assad with both financial and military help.

The Islamic State group seized territory from both Syrian government forces and rival rebels over the weekend further expanding the caliphate it has proclaimed straddling Iraq and Syria.

The Syrian Observatory for Human Rights said that following gains in both Homs province in the center and Aleppo province in the north, IS now controlled half of the country's land area.

An Iranian officer has been killed near the Iraqi city of Ramadi while advising Iraqi forces on how to recapture it from the Islamic State group, state media reported Monday.

Jassem Nouri, who had also served as a military adviser in Syria, was killed on Thursday, Iran's official IRNA news agency reported.

A brawl broke out in the early hours of Monday morning between Sudanese and Eritrean migrants in the northern French port of Calais, resulting in 24 injuries, 14 of which required hospital treatment.

According to the emergency services, the fight began after a makeshift tent was torched and escalated quickly into running battles with iron bars.

Kurdish militia in Syria wrested control of a dozen villages from the extremist Islamic State group either side of the jihadist's bastion province of Raqa on Sunday, a monitor said. 

The Syrian Observatory for Human Rights said the Kurdish People's Protection Units, backed by air strikes from a U.S.-led anti-IS coalition, seized eight villages from jihadists on the western edges of Raqa province.  

The anti-IS coalition will meet in Paris Tuesday after a series of shock battlefield gains by the jihadists, with Iraq under pressure to step up its fight by being more inclusive of the Sunni minority.

The main focus of the meeting will be the crisis in Iraq, where the Islamic State group seized the city of Ramadi two weeks ago in the biggest blow to the U.S.-led coalition since it began bombarding jihadist positions in August.

Regime air strikes killed at least 20 civilians in a rebel-dominated area of northwestern Syria, a monitor said Sunday after raids elsewhere in the country left more than 70 dead.

"The regime's planes have committed another massacre, this time in Jabal al-Zawiya," a mountainous region in the province of Idlib, the Syrian Observatory for Human Rights said of the Saturday bombing.

The U.N. envoy to Syria condemned the reported killing of more than 70 civilians by barrel bombs dropped by government helicopters on northern Aleppo province.

"The news of aerial bombing by Syrian helicopters on a civilian market area of the Aleppo neighborhood of Al-Shaar deserves the most strong international condemnation," envoy Staffan de Mistura said in a statement after Saturday's attack.

The municipal chief of the northeastern border town of Arsal Ali al-Hujeiri stressed the need for the army to seize control of security in the area and protect its citizens in light of recent fears of a possible attack by militants following battles in Syria's Qalamoun, reported the pan-Arab daily Asharq al-Awsat on Sunday.

He told the daily: “The army alone is responsible for the situation on the outskirts of the area, not Hizbullah chief Sayyed Hassan Nasrallah or local clans.”