Activists hold placards during a demonstration against the military strike on Syria in front of the White House in Washington D.C., capital of the United States, Aug. 29, 2013. Amid signs the U.S. is ready to attack Syria, 140 members of the U.S. House of Representatives have signed onto a letter, demanding President Barack Obama get authorization of Congress before going ahead with the military strike. (Xinhua/Zhang Jun)

Activists hold placards during a demonstration against the military strike on Syria in front of the White House in Washington D.C., capital of the United States, Aug. 29, 2013. Amid signs the U.S. is ready to attack Syria, 140 members of the U.S. House of Representatives have signed onto a letter, demanding President Barack Obama get authorization of Congress before going ahead with the military strike. (Xinhua/Zhang Jun)

Activists hold placards during a demonstration against the military strike on Syria in front of the White House in Washington D.C., capital of the United States, Aug. 29, 2013. Amid signs the U.S. is ready to attack Syria, 140 members of the U.S. House of Representatives have signed onto a letter, demanding President Barack Obama get authorization of Congress before going ahead with the military strike. (Xinhua/Zhang Jun)

Activists hold placards during a demonstration against the military strike on Syria in front of the White House in Washington D.C., capital of the United States, Aug. 29, 2013. Amid signs the U.S. is ready to attack Syria, 140 members of the U.S. House of Representatives have signed onto a letter, demanding President Barack Obama get authorization of Congress before going ahead with the military strike. (Xinhua/Zhang Jun)

Activists hold placards during a demonstration against the military strike on Syria in front of the White House in Washington D.C., capital of the United States, Aug. 29, 2013. Amid signs the U.S. is ready to attack Syria, 140 members of the U.S. House of Representatives have signed onto a letter, demanding President Barack Obama get authorization of Congress before going ahead with the military strike. (Xinhua/Zhang Jun)

Activist hold placards during a demonstration against the military strike on Syria in front of the White House in Washington D.C., capital of the United States, Aug. 29, 2013. Amid signs the U.S. is ready to attack Syria, 140 members of the U.S. House of Representatives have signed onto a letter, demanding President Barack Obama get authorization of Congress before going ahead with the military strike. (Xinhua/Zhang Jun)