Donald Trump has taken aim at Joe Biden's religious credentials by saying he will "hurt God" if he's elected president this year. 

Biden is a churchgoing Catholic who has often spoken about the role of his faith in coming to terms with the loss of his first wife and daughter in a car accident in 1972. 

On Thursday, his campaign spokesman Andrew Bates said in a statement: "Joe Biden's faith is at the core of who he is; he's lived it with dignity his entire life, and it's been a source of strength and comfort in times of extreme hardship."

But as the presidential election battle heats up, Trump is keen to be seen as the man for America's Christians. 

During a trip to Ohio, Trump dismissed Biden's faith, saying the Democratic contender is "against God" and "against guns". 

"He's following the radical left agenda," he said. 

"Take away your guns, destroy your Second Amendment. No religion, no anything, hurt the Bible, hurt God.

"He's against God, he's against guns, he's against energy, our kind of energy."

Vice-President Mike Pence has also been wooing the core Republican base with his "Faith in America" campaign events. 

He suggested the fate of the nation was at stake this November as he warned that the Democrats have been "overtaken" by radical Leftists. 

"The question is not whether our country will be Republican or Democrat or blue or red, but whether America will still be America," he told CBN News. 

"Joe Biden and the Democratic Party have been overtaken by the radical left.

"He's calling for a historic increase in funding to Planned Parenthood of America. He would appoint activist judges to our courts, who would literally trample on the progress that we've made on life and religious liberties."