ATHENS/FRANKFURT (Reuters) – Greek borrowing costs leapt and bank shares were hammered on Thursday after the European Central Bank abruptly pulled the plug on its funding for the country’s financial sector in what Athens labelled an act of coercion. The ECB decision to cancel its acceptance of Greek bonds in return for funding shifts the burden onto Athens’ central bank to finance its lenders and marks a further setback for the government’s attempt to negotiate a new debt deal with its euro zone peers.