Moscow on Monday accused Washington of stalling on the enforcement of a ceasefire in war-torn Syria that took effect late last month and warned it could respond to truce violations unilaterally. 

"The delay in the entry into force of the rules agreed upon for responding to violations of the ceasefire in Syria is unacceptable," lieutenant general Sergei Rudskoy said in a statement, accusing Washington of showing "no readiness" to discuss the agreement with Russia.