WASHINGTON (Reuters) - Opposition to the Iraq war has climbed to a record high and President George W. Bush’s approval rating dropped to a new low amid growing dissent from members of his own Republican party over his war strategy, according to a new USAToday/Gallup poll.

Bush’s approval dropped to 29 percent in the poll taken Friday through Sunday, down from 33 percent in early June, USA Today reported on Tuesday.

One in five Americans said the increase in U.S. forces in Iraq this year has made the situation there better while half said it has made no difference, the newspaper said.

More than seven in 10 Americans favor withdrawing nearly all U.S troops from Iraq by April, the newspaper said.

More than half, 55 percent, said Congress should wait to hear an assessment from Gen. David Petraeus before developing new Iraq policy, the report said.

Petraeus, the commander of U.S. forces in Iraq, is due to deliver his findings in September, but 40 percent of those polled said Congress should act now, the paper said.

Sixty-two percent of those polled said the United States made a mistake in sending troops to Iraq, marking the first time that number has topped 60 percent in this survey, USA Today said.

The poll also showed support for Bush slipping among Republicans who gave him a 68 percent rating, down from an average 92 percent in his first term and 82 percent earlier in his second, USA Today said.

According to the report, nearly four in 10 Republicans cited the immigration debate, which ended in defeat for Bush’s overhaul proposal, as the reason for losing confidence in him.

The poll of 1,014 adults, taken Friday through Sunday has an error margin of plus or minus three percentage point.