Russia and the Assad regime resumed intensive airstrikes on civilian areas in northwestern Syria's Idlib province and the northern Hama region Sunday amid Turkey's push for the continuation of a cease-fire to find a political solution and prevent civilian losses. The regime stepped up its assault on the last opposition stronghold, local sources and observers said, following the tripartite summit between Turkey, Russia and Iran that was held on Friday. Regime helicopters dropped barrel bombs – typically filled with high explosives and shrapnel – on the al-Habeet and Abdin villages in southern Idlib and a string of other hamlets and villages in the area.

Russian jets were believed to have joined the airstrikes and hit the nearby towns of Latamneh and Kafr Zeita in northern Hama in a succession of raids, monitoring groups and opposition sources said Sunday. The White Helmets said that a hospital in Latamneh was damaged as result of the airstrikes and was taken out of operation. Also, an infant girl was killed, the group reported. Foreign Minister Mevlüt Çavuşoğlu said on Saturday that he expects clashes to end in Idlib and a political process to resolve the issue, adding Turkey is making efforts to do so with Russia and Iran. Speaking to the press in the Mediterranean province of Antalya, Çavuşoğlu warned against the possibility of a "serious humanitarian tragedy" in Idlib, reiterating the fact that the region is a de-escalation zone where 3.5 million people live.

The presidents of Turkey, Russia and Iran came together in Tehran to find a solution to the 7-year-old Syrian war, as part of the Astana peace process.

During a joint press conference with Russian President Vladimir Putin and the host of the summit Iranian President Hassan Rouhani, President Recep Tayyip Erdoğan said it was vital to protect civilians, particularly in the northwestern Idlib region, and that terrorist elements should be separated from civilians.

"Don't let people die," Erdoğan said and urged for an immediate cease-fire to be established. "If we can declare a cease-fire here, it will be one of the most important steps of the summit, and it will relieve the civilians."

In the joint statement, announced after the summit, the parties called on the U.N. and its humanitarian agencies to help Syria by providing additional humanitarian aid. It added that "There could be no military solution to the Syrian conflict" and said that the ongoing conflict in Syria "can only end through a negotiated political process."

However, at least 26 civilians have been killed and dozens injured in continuing airstrikes and attacks by regime forces and Russian warplanes in Idlib and Hama since the beginning of this month, according to the White Helmets.

As part of the efforts to limit the violence in the country, Turkey, Russia and Iran had previously agreed to establish so-called de-escalation zones across Syria, including in the northern province of Idlib and parts of neighboring Latakia, Hama and Aleppo.

Under the Astana agreement, Turkey established 12 observation points from Idlib's north to south aiming to monitor and sustain the current cease-fire agreement for the de-escalation zones, deliver humanitarian aid and ensure the secure return of displaced people. The first of the trilateral summit at a presidential level was held last year in Russia's Black Sea city of Sochi and the second meeting was held in Ankara this year in April.

In a joint statement released after the summit, the parties called on the U.N. and its humanitarian agencies to help Syria by providing additional humanitarian aid. It added that "there could be no military solution to the Syrian conflict" and said that the ongoing conflict in Syria "can only end through a negotiated political process."

The Republican People's Party (CHP), on the other hand, prepared a six-article proposal about the situation in the Idlib, suggesting Ankara get in touch with the regime.

CHP Deputy Chairman Ünal Çeviköz presented the party's proposal regarding the issue, which called on Ankara to push efforts of calling on all opposition groups to lay down arms.

"Idlib is a national security issue for Turkey. Aside from stressing this in talks with Moscow and Tehran, it is time to get in touch with the Syrian regime and rejuvenate the spirit of the 1998 Adana Agreement between the two neighboring countries," the CHP's suggestions included.

Interior minister warns against mass migration

Interior Minister Süleyman Soylu said Sunday that Turkey will not be responsible for the migration wave in case of any attacks on Idlib.

Speaking to reporters in Yayladağı, Hatay near the Syrian border, Soylu said that Turkey is facing with one of the most major refugee crisis in world's history due to the civil war in Syria, adding that some Syrians started to return to their homes with Ankara's efforts.

"Some 255,300 Syrians have returned to their homes over the past two years, 160,000 of them returned to Operation Euphrates Shield region after Turkey brought peace there," he said.

Turkey launched Operation Euphrates Shield with the Free Syrian Army (FSA) in 2016 to drive Daesh terrorists from its borders. As a result of operation, nearly 3,000 Daesh terrorists were eliminated and a 2,000-square-kilometer area in northern Syria was liberated, including Jarablus, Dabiq and al-Bab.

The U.N. warned earlier this week that such an offensive would lead to the "worst humanitarian catastrophe in the 21st century."