An eerie silence lay over the courtyard of Ramadan al-Suleiman's nursery in northern Syria on Sunday as he picked his way through smashed cinderblocks, twisted metal and broken plastic swings.

The modest nursery in the town of Jandaris - about 70 km (44 miles) from the city of Aleppo - once hosted 100 toddlers, whose dusty pictures now lay strewn among the debris caused by Monday's devastating earthquake. Some of those children and teachers would not be coming back, Suleiman said.

"We lost two of the female teachers from the important cadres at the school. We lost seven or eight students that we know of," he told Reuters.

They were among more than 2,600 people reported so far to have died in the earthquake in opposition-held parts of northern Syria. More than 3,500 were killed across Syria in total and nearly 30,000 in Turkey.

Children's education in Syria was already hard hit by the war that has raged since 2011. For years, schools would regularly shut because of fighting, mortar fire by rebel groups or air strikes by the Syrian government or Russia.

The earthquake destroyed more than 115 schools in Syria and damaged hundreds more, according to a United Nations update published Saturday.

More than 100 others were being used as makeshift shelters to host thousands displaced by the earthquake, which brought apartment blocks and even tiny rural homes crashing down on residents' heads.

Suleiman has been trying to track down some of the nursery children from whose families he has not heard.

"I went around to buildings where I know some of the students live - and 90% of them were destroyed. There are some pupils that I suspect are dead because we cannot reach their families at all," he said.

Jandaris was particularly devastated, with many concrete buildings pulverised.

Rescuers across Syria, including in the north, have been pulling young children out from under the rubble - some of them miraculously alive even almost a week after the quake, but orphaned.

Others did not make it.

Mohammad Hassan said he still doesn't know what happened to his seven-year-old daughter Lafeen's friends and classmates.

"We asked around and discovered that one of her teachers died, may God bless her soul," Hassan told Reuters as Lafeen played quietly in his lap.

"She is shocked, she asks me to go see if something happened to the kindergarten. I'm telling her nothing happened and I will take you there once it reopens."