Greece’s government signaled the biggest concessions so far as talks with lenders on a cash-for-reforms package started in earnest on Thursday, but tried to assure leftist supporters it had not abandoned its anti-austerity principles. Prime Minister Alexis Tsipras’s three-month-old government is under heavy pressure at home and abroad to reach an agreement with European and IMF lenders to avert a national bankruptcy. A new poll showed over three-quarters of Greeks feel Athens must strike a deal at any cost to stay in the euro.