Dozens of families fled the Islamic State group-controlled Syrian town of Palmyra on Tuesday after unprecedented heavy government air strikes which killed at least five people, a monitor said.

"In the last 48 hours, more than 90 raids have been launched against the residential part of the town," Syrian Observatory for Human Rights chief Rami Abdel Rahman said.

Syria's parliament on Tuesday approved a deal with Iran under which Tehran will provide the government a new line of credit worth $1 billion, state media said.

The credit line will be the third that Tehran has extended to Damascus since the conflict in Syria erupted with anti-government protests in March 2011.

A Franciscan priest serving in northern Syria has gone missing and is feared to have been kidnapped by Al-Qaida affiliate Al-Nusra Front, his religious superiors and monitoring groups said Tuesday.

The Franciscan Custody of the Holy Land, with which he is affiliated, said it lost contact on Saturday with Father Dhiya Aziz, a parish priest at Yacoubieh, in the northwestern Idlib province.

The U.S. special envoy for the coalition against the Islamic State (IS) group was in Ankara on Tuesday to meet Turkish officials, after speculation Turkey could launch a military intervention inside Syria, sources told AFP.

"General John Allen will hold talks in Ankara today," a Turkish official told AFP on condition of anonymity, adding that the talks were "naturally" expected to focus on the fight against IS.

Kurdish fighters battled the Islamic State group in northern Syria on Tuesday after President Barack Obama said the U.S.-led coalition was intensifying its campaign against the jihadists in the conflict-riven country.

The extremist group launched a major offensive on Monday against villages controlled by the Kurds in the northern provinces of Raqa and Hasakeh, prompting fierce clashes.

Spanish police arrested Tuesday a woman on the Canary Islands suspected of recruiting girls and teenagers for the Islamic State group, the interior ministry said.

The woman, who was arrested on Arrecife on the island of Lanzarote, "maintained direct contact with Daesh operatives in Syria," it said in a statement, using an acronym for the IS group.

Britons laid flowers at the sites of the 2005 London suicide bombings and held a nationwide minute of silence for the 52 victims on Tuesday on the tenth anniversary of the attacks.

Prime Minister David Cameron led the tributes by placing a wreath at a memorial in Hyde Park, less than a fortnight after an attack in Tunisia in which 30 Britons were killed.

A suicide bomber from al-Qaida's Syrian affiliate, Al-Nusra Front, killed 25 soldiers and fighters loyal to President Bashar al-Assad's regime in an attack on an army base in government-held western Aleppo on Monday, a Britain-based monitoring group said.

The attacker blew himself up inside a vehicle "in front of an orphanage used by the regime as a base in Al Zahra neighborhood," the Syrian Observatory for Human Rights director Rami Abdel Rahman told Agence France Presse.

President Barack Obama said Monday the U.S.-led coalition battling Islamic State jihadists was "intensifying" its campaign against the group's base in Syria, but cautioned the fight would be long.

Obama addressed the media after a briefing at the Pentagon with top military brass and members of his national security team on efforts to dismantle the jihadist group, which has taken over large swathes of territory in Iraq and Syria.

Israel has arrested six Bedouin Arabs, including four teachers, for allegedly supporting the extremist Islamic State group, the domestic security service said Monday.

The six men, all members of the same family, were relatives of two people who already traveled to Syria to fight alongside jihadists, Israeli media said.