ANKARA (Reuters) - Turkey and Russia signed an agreement on Wednesday to establish a joint centre to coordinate efforts for monitoring a ceasefire in the Nagorno-Karabakh region, President Tayyip Erdogan said.He said Ankara would also participate in a peacekeeping force, but a senior Turkish security source said it would be sending observers, not peacekeepers. The ceasefire between Azerbaijan and Armenia was announced on Tuesday, ending the worst fighting in the region in decades, and celebrated as a victory in Azerbaijan and its ally Turkey. Deployment of Russian peacekeeping troops on Tuesday locked in Azerbaijan’s territorial gains.