NATO Secretary General Jens Stoltenberg accused Russia of undermining efforts to reach a peaceful solution in Syria by targeting opposition groups instead of DAESH terrorists and said lasting peace would only be achieved if this is stopped.
"Russia has mainly targeted opposition groups and not ISIL [DAESH]. Air strikes of Russian planes against different opposition groups in Syria have actually undermined the efforts to reach a negotiated, peaceful solution," he said.
His comments came after major powers, including Russia, reached agreement on plans for a ceasefire between opposition and regime forces in Syria, although Moscow has said it will continue bombing terrorists.
"What we need is a lasting ceasefire, we need help for the civilians and we need of course an agreement on transition," Stoltenberg added.
On Wednesday, the United Nations Security Council also called on Russia to halt bombing around Aleppo in support of Syrian regime forces, which has been accused of worsening the dire humanitarian crisis in the area.
The statement came after the UN warned that hundreds of thousands of civilians could be cut off from food supplies if opposition-held Aleppo is encircled by Russia-backed Syrian regime forces.
At least 500 people have been killed from both sides during the fighting in Aleppo province since the start of a Syrian regime and allied forces offensive began in early February, a war monitor said on Wednesday.,
The offensive to surround Aleppo amounts to one of the most significant shifts of momentum in the five-year civil war, in which 250,000 people have been killed and 11 million others have been forced to flee their homes.
The European Union Council President Donald Tusk said on Tuesday that Russian air strikes in Syria are making a bad situation worse by helping regime leader Bashar al Assad, weakening the moderate opposition and triggering fresh waves of refugees fleeing toward Europe.
German Chancellor Angela Merkel also raised the issue of Russian intervention to the Syrian conflict in a recent visit to Turkey on Monday.
Merkel said that she is shocked by the suffering of civilians in Syria because of regime advances backed by Russian bombing, speaking during a joint press conference with her Turkish counterpart Ahmet Davutoglu.
United States Secretary of State John Kerry said that constant Russian bombardment has recently killed many civilians in Syria, demanding an immediate halt of Moscow’s air strikes which local opposition sources have said exceeded 100 sorties on a single day at times.
The Western powers and Turkey have consistently criticised Moscow for targeting opposition forces and civilians rather than DAESH, as rights groups have accused Russia of committing war crimes.
According to the monitoring group Syrian Observatory for Human Rights (SOHR), nearly 1,400 civilians have been killed in Syria by Russian air strikes since September 2015.