PARIS (Reuters) - Russia and Serbia have signed a cooperation agreement on civil nuclear energy, state-owned Russian reactor builder Rosatom said in a statement on Thursday.

The intergovernmental agreement covers construction and modernization of research nuclear reactors and nuclear medicine development. That it comes so soon after a previous deal, signed by Russia and Serbia in Sochi last year, could signal more concrete steps ahead.

Rosatom has nuclear cooperation deals with dozens of developing countries. These agreements are not contracts to sell Russian-design nuclear reactors. They can be a first step toward such a deal, but often talks go on for years with little progress.