Russian president Vladimir Putin has met with his Turkish counterpart Recep Tayyip Erdogan inIstanbul. Both leaders vowed to intensify their relations once again following an 11-month diplomatic row. As they signed an agreement to build strategic gas pipelines under the Black Sea connecting the two countries -- effectively by-passing Ukraine -- Putin said the two countries could now return to cooperation in all areas.

When Turkey shot down a Russian war plane last November, it led to the worst dispute between the pair since the Cold War. Erdogan said he is confident they can normalize their relations going forward.