The overnight bombing of the Syrian city of Aleppo is hugely disappointing, Prime Minister John Key says.
The United Nations Security Council today held an emergency meeting as Aleppo sustained heavy bombing, with the Syrian government saying it had launched an offensive to retake rebel-held areas.
At the meeting, the American ambassador to the UN accused Russia of barbarism not counter-terrorism.
Russia said achieving peace in Syria was now almost impossible.
Mr Key, who chaired the Security Council last week, said after more five years of brutal fighting, and horrific humanitarian suffering, Syria had become the greatest crisis of our time.
"It is despicable that civilians are bearing the brunt of the renewed fighting. The immediate priority must be to stop the fighting and the targeting of civilians.
"The parties must also commit to restoring the ceasefire, delivering aid to those who need it and restarting political talks."