SINGAPORE - US stock futures fell 1 percent and US Treasury futures rose on Tuesday, with investors seeking liquidity and shunning risky assets after a plunge on Wall Street overnight.US S&P 500 futures expiring for September were down to around 1,101 -- the lowest since September 2010 -- suggesting U.S. stocks are poised for more selling.US Treasury futures were up 8/32 to 128-27/32 , the highest since December 2008.