The Turkish military on Thursday pounded positions held by Islamic State (IS) militants in Syria after a Turkish soldier was killed by fire from an area controlled by the jihadists.

The clashes -- the most serious yet between the Turkish army and IS -- came after the killing of 32 people in a suicide bombing Monday, blamed on IS, sparked an upsurge in violence.  A day after the fatal shooting of two police claimed by Kurdish militants as "revenge" for the suicide bombing in the town of Suruc on the Syrian border, a policeman was shot dead in the majority Kurdish city of Diyarbakir.

The U.N.'s envoy to Syria met with its foreign minister in Damascus Thursday as part of ongoing efforts to negotiate a solution to the four-year war, state media said.

"Staffan de Mistura presented the latest developments linked to his discussions and meetings in multiple countries" to Syrian Foreign Minister Walid Muallem, the official SANA news agency reported. 

Favorable rains have helped Syria's 2015 wheat harvest but the country's food insecurity is worsening overall because of war, two U.N. agencies said on Thursday.

Food production "remains way below its pre-crisis levels as the ongoing conflict continues to push more people into hunger and poverty," the Food and Agriculture Organization (FAO) and the World Food Program (WFP) said in a report.

A militant group allied to Turkey's outlawed Kurdish party has shot dead in Istanbul an alleged member of the Islamic State group who had fought in Syria, media said Thursday.

The reports come amid soaring tensions in Turkey following Monday's suicide bombing in the town of Suruc on the border with Syria that killed 32 and that the authorities blamed on IS.

EU foreign affairs chief Federica Mogherini will visit Iran and Saudi Arabia next week following the agreement she helped broker with Tehran on its contested nuclear program, her office said Thursday.

The talks in Saudi Arabia on Monday will cover "regional issues, in the aftermath of the agreement reached on 14 July on the Iranian nuclear issue, as well as international issues of common interest," a statement said.

Pentagon chief Ashton Carter flew to Baghdad Thursday for talks on Iraq's war against the Islamic State group, whose "caliphate" is shrinking but is ramping up deadly car bombings.

Carter was to meet Prime Minister Haider al-Abadi and Sunni Arab tribal leaders from Anbar, the province where much of the fighting has taken place in recent weeks.

Spanish intelligence agents were working urgently Wednesday to track down three journalists from Spain, the latest foreigners to go missing while reporting in war-torn Syria.

Prime Minister Mariano Rajoy said "no theory was ruled out" over what has happened to the three, missing for 10 days in a war zone where numerous foreigners have been kidnapped in the past.

A young Turkish doctor who was pictured holding the hand of her friend in the aftermath of the suicide bombing on the Syrian border has survived her injuries and been transported to Istanbul for treatment, the Hurriyet daily said Wednesday.

In a picture that rapidly went viral on social media, two women were shown lying flat on their backs on the ground following the attack in the border town of Suruc that killed 32 people.

Turkey on Wednesday identified the perpetrator of a deadly suicide bombing blamed on Islamic State (IS) extremists as a 20-year-old man from its southeast, as the government prepared new measures to protect the porous border with Syria.

With the country still shaken by Monday's bombing in Suruc, close to the Syrian border, two police were found shot dead in their homes in a nearby town but it was unclear if there was a terror link.

The military wing of the outlawed Kurdistan Workers' Party (PKK) said on Wednesday it killed two Turkish police officers in a town on the Syrian border as a reprisal for a suicide bombing blamed on jihadists that killed 32.

"A punitive action was carried out... in revenge for the massacre in Suruc," the People's Defense Forces (HPG) said in a statement on its website, accusing the two officers of cooperating with the jihadists.