US election: Barack Obama and Mitt Romney campaign in swing states

1. Mitt Romney reaches out to shake hands with supporters as he campaigns at Colorado Springs Municipal Airport.

US election: Barack Obama and Mitt Romney campaign in swing states

2. Mitt Romney holds a rally at Colorado Springs municipal airport

US election: Barack Obama and Mitt Romney campaign in swing states

3. Mitt Romney and his wife Ann greet supporters during a campaign rally in Englewood, Colorado

US election: Barack Obama and Mitt Romney campaign in swing states

4. Barack Obama shows signs of exhaustion as he speaks during a campaign rally in Aurora, Colorado

US election: Barack Obama and Mitt Romney campaign in swing states

5. Fireworks explode over a Romney campaign rally in Morrisville, Pennsylvania

US election: Barack Obama and Mitt Romney campaign in swing states

6. US President Barack Obama is greeted by former President Bill Clinton during a campaign rally in Concord, New Hampshire

US election: Barack Obama and Mitt Romney campaign in swing states

7. US President Barack Obama speaks during a campaign rally in Concord, New Hampshire

US election: Barack Obama and Mitt Romney campaign in swing states

8. Barack Obama greets supporters during a campaign rally in Concord, New Hampshire

US election: Barack Obama and Mitt Romney campaign in swing states

9. Mitt Romney arrives at a campaign rally in Des Moines, Iowa

US election: Barack Obama and Mitt Romney campaign in swing states

10. Mitt Romney greets supporters as he poses with children during a campaign rally at the Hy Vee Centre in Des Moines, Iowa

US election: Barack Obama and Mitt Romney campaign in swing states