The rebel group Jaish al Islam said in a statement that, despite the announced truce, government and allied forces had attacked the town of Maydaa, in the Eastern Ghouta area east of Damascus.
US Secretary of State John Kerry welcomed the announcement, adding that discussions were under way to try to extend the truce.
The truce was reached late Tuesday and officially went into effect Wednesday. U.S.
Aleppo, Syria's largest city, has struggled through intense violence for nearly two weeks as diplomats have worked to rebuild the February truce. Approximately 300 people have died during that time, with hospitals and civilian buildings hit.
They then came together to perform the song to mark the truces
from 100 years ago.
Dr Megoran and his team have put together a resource pack for schools and churches to help them commemorate the truces..
Heaton Baptist Church in Newcastle upon Tyne and the Northumberland Hussars - who were present at the first Christmas truce 100 years ago - are hosting a commemoration service of peace on Sunday, December 21, at 6pm.
Agreement on the truces varies according to the FSA's strength and resources, as well as geography, activists say.
Another FSA source said truces were more likely to be resisted in areas where the FSA has greater firepower and resources.
An academic appealed for help yesterday to establish whether British and German troops really played football matches during the Christmas truce
A holiday that both sides recognize might do it, as happened in the Christmas truce
during World War I.
The story of the Christmas Truce
is a popular holiday story in Europe, highlighting a moment of hope in a dark and dreary war.