Turkey's Prime Minister Recep Tayyip Erdogan  on Thursday accused ratings agency Standard & Poor's of bias for lowering the country's long-term credit outlook on the same day it upgraded Greece's credit grade. S&P on Tuesday had dropped Turkey's outlook from positive to stable, which mean it is no longer considering an upgrade of its credit rating, and cited concerns over government debt. The same day it had upgraded the ratings of neighboring Greece after Athens completed a major debt writedown with private creditors. The government of Turkey, a traditional rival to Greece, was less than pleased. "'From now on, we do not recognize you as a ratings agency,'" said Recep Tayyip Erdogan, who said S&P's ratings decisions this week were "ridiculous." S&P explained Wednesday that despite a terrific decade of economic growth and development, several structural weaknesses continue to put pressure on Turkey. "Its economy is fairly closed, with exports accounting for a small share of GDP (about 24 percent in 2011)," S&P said in a statement. It noted the current account deficit is large and highly dependent on short-term financing from outside Turkey. As a result, Turkey is particularly vulnerable to sudden financial account outflows and refinancing risks, S&P warned.