However, Mao decided against further escalation because he feared that India would retaliate by permitting the U.S. to station U-2 surveillance aircraft on its territory. This would allow the CIA to photograph China's nuclear test site at Lop Nor in Xinjiang. A few days after Kongka Pass, Chinese Prime Minister Zhou Enlai proposed that each side withdraw 20 kilometres from a "Line of Actual Control". He defined this line as "the so-called McMahon Line in the east and the line up to which each side exercises actual control in the west". Nehru responded with a proposal to turn the disputed area into a no man's land.