Washington: President George Bush has marked the fifth anniversary of the US-led invasion of Iraq saying the military adventure was worth the “high cost in lives and treasure.''

The speech comes as Bush's approval ratings are near record lows, with just under a year left in his presidency.

Bush said successes in the Iraq conflict – which has cost almost 4,000 American lives and cost up to $ 500 billion – were “undeniable.''

As he spoke, thousands of people took to the streets across the country to demonstrate against the war.

As war-weary Americans deal with economic hardship and a declining dollar, as well as upcoming presidential elections, Bush is working hard on shoring up support for Iraq and winning back the attention of the nation.