Russian Foreign Minister Sergei Lavrov said Monday Russia and the United States never held secret meetings about a possible regime overthrow in Syria. \"We never hold secret discussions with anyone over the fate of a third-party country, and there was no secret discussion with the [United States] or with anyone else about [Syrian President] Bashar Assad,\" Lavrov said from Cairo. Russia and the United States have traded barbs over their roles in the Syrian conflict, which began in March 2011 when anti-government rebel forces began protests, RIA Novosti reported. Russia has criticized the United States for supporting anti-Assad forces, saying they are interfering with the domestic affairs of a foreign state. The United States has slammed Russia for allegedly enabling Assad\'s violent regime by supplying arms to Damascus. Lavrov said Russia is fulfilling an old contract to supply defense equipment. \"Currently, we are fulfilling our earlier commitments, mainly relating to the supply of air defense systems,\" Lavrov said. \"Such weapons are defensive in nature and do not conflict with international obligations.\"