UNITED NATIONS, March 5 (Xinhua) -- UN Secretary-General Antonio Guterres "was shocked to learn that airstrikes on populated areas are continuing in northwest Syria" as ceasefire talks were underway in Moscow, his spokesman, Stephane Dujarric, said on Thursday.

"He reminds all parties of their obligation under international law to protect civilians and civilian infrastructure," Dujarric said.

"The secretary-general takes note that Russia and Turkey have reached an agreement at the highest level for a ceasefire to go into effect in the Idlib de-escalation area as of midnight (Thursday)," the spokesman said.

"The secretary-general hopes that this agreement will lead to an immediate and lasting cessation of hostilities that ensures the protection of civilians in northwest Syria, who have already endured enormous suffering," Dujarric said.

Turkish President Recep Tayyip Erdogan said earlier in the week that he would seek a ceasefire deal in Idlib during a Thursday meeting with his Russian counterpart Vladimir Putin.

The United Nations has stepped up the cross-border critical humanitarian needs initiative from Turkey for hundreds of thousands of newly displaced women, men and children in northwest Syria, the spokesman said.

"From March 1-4, 130 trucks carrying food, shelter material, water, sanitation and hygiene and nutrition assistance for over 309,000 people have been sent into the northwest part of Syria through the Bab al-Hawa and Bab al-Salam border crossings, as authorized by the Security Council," he said. "This is in addition to more than 2,000 trucks that went through in January and February."

"This assistance is saving lives, but as we have been clear, more has to be done to meet these high needs," Dujarric said. "The United Nations is currently pushing for more trucks to be able to go through the border."

The UN Office for the Coordination of Humanitarian Affairs in a Flash Update said the fact that almost 1 million people were displaced in the last three months deepens the humanitarian crisis in the northwest.

The most recent displacement "further aggravated the already dire situation in northwest Syria where 2.8 million people out of 4 million were already estimated to be in need of humanitarian assistance," said the update issued here.

The World Food Programme and the UN Children's Fund executive directors David Beasley and Henrietta Fore wrapped up a two-day visit to Syria, and said in a joint statement that "it is now more urgent than ever to end the violence in the country and to improve access across the country."

The two agency chiefs also underlined the need to provide families in Syria with basic services and to improve their economic conditions.