US Vice President Kamala Harris and former President Donald Trump held competing events to appeal to voters in the battleground state of Pennsylvania on the eve of the country's presidential election.

The two have remained neck and neck in recent polls.

Both Harris and Trump visited the state, which has the largest number of electors among the seven battleground states, on Monday night.

Democratic nominee Harris held a rally in the former site of a steel facility in Pittsburgh, the state's second largest city.

She said: "We are not going back, because America is ready for a fresh start, and we are ready for a president who knows the true measure of a leader is not based on who you beat down. It is based on who you lift up."

Republican nominee Trump spoke at an indoor arena also in the city. He said, "Kamala Harris has delivered soaring prices and economic anguish at home, war and chaos abroad."

He added, "We will begin the four greatest years in the history of our country, and we will launch the most extraordinary economic boom the world has ever seen."

Later in the day, Harris will hold her final campaign rally in the state's largest city of Philadelphia, while Trump is scheduled to speak in another battleground state, Michigan.