Similar to the fact that there is no peacekeeping without a peace to keep there can be no ceasefires unless all sides cease firing. Evidence Sudan:
...The United Nations and African Union have condemned the Sudanese army and Janjaweed militias for attacking rebels in Darfur's Jebel Moon area.
They denounced the government violation of a May peace agreement and expressed concern for the safety of civilians.
This is the first time since the peace deal that the Sudanese army has been confirmed as fighting in Darfur.
The attack was against the rebel Justice and Equality Movement, (JEM) which did not sign the deal.
To be fair this is not a bilateral situation. The Sudanese army and a rebel group which it signed a ceasefire with have used the ceasefire as a means to turn their guns on rebel groups that did not sign on.
