The European Union has called for an end to the bombings in northwest Syria and the opening of a humanitarian corridor as Syrian forces push into the last rebel stronghold of Idlib.

Josep Borrell, the EU's diplomatic chief, said on Thursday "bombings and other attacks on civilians in northwest Syria must stop".

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In a joint statement with European Emergency Response Coordinator Janez Lenarcic, Borrell called for "unimpeded humanitarian access to people in need of assistance" as well the "respect of humanitarian law, including the protection of civilians".

The EU reiterated its willingness to provide humanitarian assistance in the face of "the extraordinary human suffering being endured by the population", but called for "unhindered and secure access to assess and respond to the full range of needs".

Al Jazeera's Sinem Koseoglu, reporting from a refugee camp in Syria's rebel-held Atmeh, said the situation was "very dire" in the area.

"Atmeh centre, a tent city, is very crowded. People have no infrastructure. There aren't enough tents," she said.

Koseoglu said the aid could enter from Bab al-Hawa from Turkey's Hatay region, but the security situation made it difficult to do so as the Syrian government has conducted raids against its own citizens.

"People feel stuck by the border. They can't enter Turkey, they can't go back home, they can't receive proper aid and public service," she said.

Renewed offensive

Backed by Russian airpower, the Syrian government forces have intensified its attacks since December to gain ground in Idlib.

A renewed offensive by Syrian forces has undermined existing peace agreements and led to deadly clashes between Turkish and Syrian forces in which more than 20 soldiers and personnel were killed on Monday.

Syrian army soldiers advance in Tall Touqan village in Syria's northwestern Idlib province [AFP]

Meanwhile, Turkey on Thursday urged Russia to press for an end to the Syrian government offensive in Idlib.

"We expect Russia to stop the regime as soon as possible," Turkey's Minister of Foreign Affairs Mevlut Cavusoglu told reporters in the Azerbaijani capital Baku.

Turkey and Russia back opposing sides in the Syrian conflict, but have worked to find political solutions in Idlib.

Cavusoglu said Turkey's President Recep Tayyip Erdogan and his Russian counterpart Vladimir Putin could meet "if needed".

Kremlin spokesman Dmitry Peskov also said there were no plans currently for Putin and Erdogan to meet, but that such a meeting could be quickly organised if needed.

The Syrian government forces backed by air raids had on Wednesday encircled and entered Saraqib, 15 kilometres (9 miles) east of Idlib city, according to a report by the British-based Syrian Observatory for Human Rights (SOHR) that was corroborated by witnesses.

The town lies at the junction of two main roads that President Bashar al-Assad seeks to fully control under the campaign to regain Idlib province, the last rebel bastion in the nearly nine-year-long civil war.

The swift advance towards Idlib city has caused a new exodus of thousands of civilians towards the border with Turkey, which backs some rebel groups fighting al-Assad.

Rebel fighters "managed to push back government forces from most of Saraqeb in an attack from the northern part of the town that coincided with Turkish shelling against advancing government forces", the SOHR said.

Witnesses said government forces came under shelling from Turkish observation posts in the area, which were established last year under a deal with Moscow.

The renewed fighting is taking place despite a January 12 ceasefire agreement between Turkey and Russia.

The conflict in Syria has killed more than 380,000 people since 2011 and has driven more than half of the pre-war population of more than 20 million people into exile.