US President George W Bush has given one of the biggest speeches of his re-election campaign, at the end of the Republican Party convention.
He defended his record, notably the wars in Afghanistan and Iraq, and set out his vision for the next four years.
Mr Bush vowed to stay "on the offensive" against terrorists worldwide, and build a safer America.
The president also launched a forthright attack on his Democratic opponent, John Kerry.
Opinion polls suggest the two candidates are running virtually neck-and-neck ahead of the presidential election in November.
Mr Bush formally accepted the Republican party's nomination, and told the convention in New York that he was "running for president with a clear and positive plan to build a safer world".
He said that after the attacks of 11 September 2001, his administration had "fought the terrorists across the Earth".
Funding for homeland security has been tripled, the military transformed and intelligence services strengthened, he told delegates.
"We are staying on the offensive, striking terrorists abroad, so we do not have to face them here at home," Mr Bush said.
The president said the strategy was succeeding, with Osama Bin Laden's al-Qaeda network chased from Afghanistan, and hunted in Pakistan and Saudi Arabia.
"Libya is dismantling its weapons programmes, the army of a free Iraq is fighting for freedom, and more than three-quarters of al-Qaeda's key members and associates have been detained or killed," Mr Bush added.
He again mounted a vigorous defence of the war in Iraq that toppled the regime of Saddam Hussein.
The president said the decision to go to war was the toughest he had faced, and at the time he asked himself: "Do I forget the lessons of September 11 and take the word of a madman, or do I take action to defend our country?
Mr Bush's speech drew an enthusiastic response from delegates
"Faced with that choice, I will defend America every time," he told delegates.
Mr Bush said 50 million people had been liberated as a result of the interventions in Iraq and Afghanistan.
He added that he was "working to advance liberty in the broader Middle East".
Mr Bush also outlined his domestic priorities.
In an echo of his main campaign theme in the 2000 election, he said he would run "with a compassionate conservative philosophy", saying government should "help people improve their lives, not try to run their lives".
The president promised legal reforms to protect businesses from "frivolous lawsuits that threaten jobs" and make the 10-year tax cut package enacted in 2001 permanent.
He also stressed improving standards in education, better health care for the elderly, more job creation and tax relief for businesses in deprived areas.
Mr Bush contrasted his policies with those of Mr Kerry, which he said would result in higher taxes.
The incumbent also derided his opponent's claim to represent "conservative values" - which Mr Bush said "must have come as a surprise to a lot of his supporters".
Kerry wasted no time in reacting to Republican attacks
In response Mr Kerry for the first time questioned the war records of both Mr Bush and vice-president Dick Cheney.
"I'm not going to have my commitment to defend this country questioned by those who refused to serve when they could have and by those who have misled America into Iraq," he told a rally in Ohio.
Republicans have accused Mr Kerry, a Vietnam veteran, of embellishing his war exploits.
Mr Bush's speech received rapturous applause - although at one stage he was interrupted by a woman heckler who was hustled out of the Madison Square Garden convention hall.
Outside, thousands of demonstrators gathered to express their opposition to the president's policies.
The four-day convention has attracted large-scale street protests with a number of arrests.