US stocks mixed amid debt clash in Washington

US stocks were mixed as markets opened Tuesday after US President Barack Obama and his Republican foes clashed again over the debt ceiling, dimming hopes of a timely resolution to the standoff. The Dow Jones Industrial Average was down 54.46 points (0.43 percent) at 12,538.34 after the first five minutes of trading. The broader S&P 500 slipped 2.25 points (0.17 percent) to 1,335.18, while the tech-heavy Nasdaq Composite climbed 1.40 points (0.05 percent) to stand at 2,844.20. Late on Monday, Obama warned of a "deep economic crisis" if Congress failed to raise the US government's $14.29 debt ceiling by August 2, while Republicans continued to reject his demand to raise taxes.