A senior U.S. military official Sunday said the U.S. government would send more helicopters, engineers and medical instruments for relief and rescue operations in Pakistan's quake-hit regions, DPA reported. "The scope of tragedy is significant and this is all about helping our friend," Commander U.S. Central Command (CETCOM), John P. Abizaid told reporters in Rawalpindi near Islamabad after a tour of the tremor-stricken regions in the Northwestern Frontier Province and Pakistan-administered Kashmir. Severed road and communication links were the main impediments to the relief and rescue missions in the areas, he said. He urged the international community and the United Nations to extend maximum assistance to Pakistan. "There are areas where people need lot of attentions and we have to reach there." About 40 U.S. helicopters including Chinook and Black Hawks are already engaged in relief and rescue operation in the affected mountain regions where a massive earthquake killed more than 51,300 people and displaced hundreds and thousands who are living without shelter in freezing temperatures. The United Nations launched another urgent appeal on Saturday. --More 2205 Local Time 1905 GMT