BRUSSELS (Reuters) - Greek Prime Minister Alexis Tsipras went on the offensive against the country's creditors on Friday, saying European principles were not based on "blackmail" and that his government would fight for mutual respect instead. Athens and its creditors remain deadlocked over a cash for reforms deal days before a debt payment to the IMF falls due, leaving Greece perilously close to bankruptcy. "The European Union founding principles were democracy, solidarity, equality and mutual respect. It was not based on blackmail and ultimatums," Tsipras told reporters after an EU summit. ...