Former Massachusetts governor Mitt Romney is heading for big victory in the Washington state Republican caucuses.

With about 60 percent of the vote counted, Romney had about 37 percent support in the straw poll. Texas Representative Ron Paul and former U.S. Senator Rick Santorum are battling for the second place with about 24 percent each, while former House speaker Newt Gingrich is running a distant fourth.

The caucus comes ahead of the so-called “Super Tuesday” voting in 10 states that could determine who will face President Barack Obama — a Democrat — in November's election.

In the latest Republican national poll , Romney has 35 percent support, while former U.S. senator Rick Santorum has 24 percent. The other candidates, Mr. Gingrich and Texas Representative Ron Paul, trail with 15 percent and 11 percent, respectively.

At stake in Washington are 40 delegates to the Republican national convention.