Former US president Donald Trump is “fine” after he was whisked off stage by Secret Service agents after gunshots were heard during a rally in Pennsylvania on Saturday, his campaign said. “President Trump thanks law enforcement and first responders for their quick action during this heinous act. He is fine and is being checked out at a local medical facility. More details will follow,” Trump spokesman Steven Cheung said in a statement. Trump had only just begun his speech in the town of Butler when the incident occurred. TV footage showed panic breaking out in the front ranks of the rally afte…