[REUTERS] The Greek central bank warned on Wednesday that the country would be put on a "painful course" towards default and exiting the euro zone if the government and its international creditors failed to reach an agreement on an aid-for-reforms deal.It also said Greece risked a renewed bout of recession and predicted that the current economic slowdown would accelerate in the second quarter of this year. The Greek economy had started growing again last year after being pounded by years of austerity, but fell back into negative growth in the first quarter of 2015, contracting by 0.2 percent year-on-year.