NEW YORK (CNN/Money) - Signs that a war with Iraq may now be inevitable, and could start in days, not weeks, spooked investors early Monday, pushing U.S. stocks lower.

At around 9:35 a.m. ET, the Dow Jones industrial average (down 53.36 to 7806.35, Charts), Nasdaq composite (down 8.67 to 1331.66, Charts) and Standard & Poor's 500 (down 4.01 to 829.26, Charts) index all declined modestly.

In the latest news on Iraq, a summit over the weekend with Britain, the United States and Spain ended with President Bush saying Monday would be the last day for diplomacy when it comes to Baghdad.

White House officials said Monday that members of the Bush administration would be making a last-ditch effort to round up United Nations Security Council support on a possible new U.N. resolution requiring Iraq to disarm and Saddam Hussein to go into exile, although this may be futile as veto-wielding members France and Russia have already made it clear that they will not support a new resolution. Meanwhile, the United States has advised U.N. weapons inspectors to leave Iraq in anticipation of likely action. (For more details on the latest developments, go to CNN.com)

In corporate news, J.P. Morgan cut its earnings estimates for the year on both Ford (F: down $0.09 to $6.67, Research, Estimates) and Dow component General Motors (GM: down $0.64 to $31.36, Research, Estimates), based on expectations for lower than expected sales and production levels in North America.

Treasury prices soared in early trading, with the 10-year note yield down to 3.65 percent from 3.71 percent late Friday. The dollar dropped against the yen.

European markets fell at midday, while Asian markets closed lower Monday.

Brent oil futures gained 32 cents to $30.45 a barrel in London. Gold was higher.