President Asif Ali Zardari Wednesday flew into Siachen to review rescue and relief operations to find survivors at the site of a massive avalanche, which has buried 138 soldiers and civilians, officials said. None of the buried men has so for been recovered since the avalanche hit a military camp on April 7 despite search and rescue operations, which are also joined by experts from several other countries. Army chief General Ashfaq Pervaiz Kayani, Interior Minister Rehman Malik and senior military officials accompanied the President in his visit, the first by any Pakistani government leader in 12 days. Officials said that the President directed the military commanders to use all resource during the rescue and search operation and assured full support of the government. He praised the rescuers for working in cold weather. Earlier on Tuesday, PML-N chief Nawaz Sharif visited the area, who also met families of the missing army men. He also announced five hundred thousand rupees aid each for family of every army man still under snow. Military officials briefed the President about the rescue and search operation at Gayari sector in Siachen, officials said. Pakistan army said that presence of toxic gases in a tunnel at as avalanche site has hampered the rescue and search operation for the survivors buried under snow. Pakistan and foreigner rescuers had identified several sites for the possible recovery of the buried soldiers and civilians. An army statement said that Swiss and German team after completing their assigned task of assisting search and rescue mission have gone back to their counties. The report submitted by Swiss and German teams validated earlier indentified sites by Pakistan Army, an army statement said. Meanwhile Norway and the U.S. teams are at the site to assist the ongoing rescue operations. Search and rescue Operation at Gayari continues round the clock at its full pace. The rise in temperature has increased the chances of slides, however necessary safety precautions are being taken to ward off danger, the army says.