Russia's top diplomat said Tuesday that about 2,000 fighters from the Middle East have joined the fighting over Nagorno-Karabakh, the worst outbreak of hostilities in the conflict between Armenia and Azerbaijan in more than a quarter-century. Russian Foreign Minister Sergey Lavrov's statement came as the warring parties traded accusations over new attacks in the region. “We are certainly worried about the internationalization of the Nagorno-Karabakh conflict and the involvement of militants from the Middle East,” Lavrov said in an interview with the Russian business daily Kommersant.