President Pranab Mukherjee on Wednesday said concerted efforts were needed to tackle terrorism which has assumed serious proportions and which threatens the international community.The president said this to officer trainees of the 2013 batch of the Indian Foreign Service (IFS), who called on him at Rashtrapati Bhavan.He said extremists appear to have access to abundant arms and resources through drug trafficking and other criminal activities."The trouble spots in the world are spreading rapidly and many important cities are being threatened. There is not only danger to historical and civilization relics in these cities, but their collapse also becomes a symbol of political destabilisation. Despite the Cold War having come to an end, the desired peace and tranquillity is still far from the reach of the people of the world," he said.Describing the current global situation as extremely complex, the president said simplistic approaches will not be sufficient to understand current trends."Indian diplomats should take note of developments in the world with utmost speed. They should develop the ability and expertise to understand and analyse them," he said.