(Reuters) -The U.S. Treasury bought Argentine pesos in the "Blue Chip Swap" and spot markets on Thursday and it continues to monitor all markets, Treasury Secretary Scott Bessent said on Friday. "Treasury is monitoring all markets, and we have the capacity to act with flexibility and with force to stabilize Argentina," he said in a post on X. It was the first announcement of participation in the "blue" market, after Bessent previously spoke of buying pesos in the open market. Both the "blue" peso and th ...