Russia would agree to a 48-hour ceasefire in Syria’s Aleppo city but would not allow it to be extended for a week said a top official on Thursday.

Russian Deputy Foreign Affairs Minister Sergei Ryabkov said they were proposing the ceasefire to guarantee civilian access to humanitarian aid but cited the US’ actions in Syria as the reason for its brevity EFE news reported.

quot;With the aim of guaranteeing access to humanitarian aid we are proposing a pause in hostilities of 48 hoursquot; the minister said at a press conference.

He added that quot;our American colleagues for reasons only they know are insisting on extending the ceasefire to seven daysquot;.

Ryabkov said a week-long ceasefire would give quot;terrorist groupsquot; time to rest restock munitions and regroup but insisted that the proposal for a two-day cessation in violence remained on the table.

He said putting an end to the Syrian conflict would require cooperation between Moscow and Washington but he insisted that Russia would not bow to ultimatums propounded by the US.

US Secretary of State John Kerry recently warned that a continued Russian offensive in Aleppo would threaten the bilateral cooperation which would hamper scheduled joint military operations targeting the Islamic State terror state.

The US has blamed Russian airstrikes in the city for civilian deaths and implicated the nation in the bombing of a UN aid convoy on September 19.

Russia denied the allegations and accused Washington of pursuing self-interest in its tactics and of supporting armed opposition groups in Syria that Moscow allied to President Bashar Al Assad considers terrorist groups.