A US reconnaisance plane is forced to land in China after a mid-air collision with a Chinese fighter jet. The crew are held by China, sparking an angry diplomatic until they are released.

The US tests its controversial missile defence shield, or "Son of Star Wars".

11 September Four passenger aircraft are hijacked and two are crashed into the World Trade Center in New York. A third hits the US Defence Department - the Pentagon - in Washington DC and a fourth crashes in Pennsylvania. More than 3,000 people are killed in the attacks.

The US leads massive campaign of air strikes against Afghanistan and later sends in special forces to help opposition forces defeat the Taliban regime. The Saudi-born dissident, Osama bin Laden, who is suspected of masterminding the September 11 attacks, is not found.

The USA Patriot Act gives the government greater powers to detain suspected terrorists, eavesdrop on communications and counter money-laundering. President Bush signs a directive to try suspected terrorists in military tribunals rather than the courts.

Energy giant Enron declares itself bankrupt after massive false-accounting comes to light.

The US refuses to sign the UN Kyoto Treaty on environmental control. Relations with the UN are further soured when the US blocks proposals to curb the illegal sale of small arms in the world and refuses to sign up to an international agreement to enforce a ban on the use of biological weapons.

2002 In his state of the Union address, President George W Bush, describes Iraq, Iran and North Korea as being part of an "axis of evil".

Telecoms giant WorldCom's multi-billion dollar accounting fraud is revealed, eclipsing the Enron scandal to become the biggest business failure in US history. The company goes into bankruptcy.

President Bush signs into law a bill creating a Department of Homeland Security, the biggest reorganisation of federal government for more than 50 years.

The large and powerful department is tasked with protecting the US against terrorist attacks.

2003 Space shuttle Columbia's 28th mission ends in tragedy when the craft breaks up while re-entering the atmosphere. The seven astronauts on board are killed.

Missile attacks on targets in Baghdad mark the start of a US-led campaign to topple the Iraqi leader Saddam Hussein. US forces advance into central Baghdad in early April.

1 May 2003 Speaking on the deck of the aircraft carrier Abraham Lincoln, President Bush declares that the main part of the war in Iraq is over.