The euro weakened to the lowest in more than two years against the dollar, falling below its lifetime average, as concern mounted that European leaders are failing to gain control of the region’s debt crisis.

The 17-nation currency slid to an 11-year low against the yen, while Japan’s currency strengthened against all 16 of its major peers as investors sought safer assets. Six Spanish regions may ask for aid from the central government, El Pais reported, propelling the nation’s 10-year bond yield to a euro- era high. The Swiss franc weakened through 99 centimes per dollar for the first time since December 2010.

“There’s just more risk out there in the euro zone, and investors are getting more worried about how things could go,” Charles St-Arnaud, a foreign-exchange strategist at Nomura Holdings Inc. in New York, said in a telephone interview. “Concern is building that Spain will probably need a formal bailout.”

The euro fell 0.4 percent to $1.2106 at 10:43 a.m. in New York after losing as much as 0.7 percent to $1.2067, the weakest since June 2010 and below the average of $1.2087 since its inception in 1999. The shared currency fell to $1.1877 in June 2010, its lowest level since 2006. The euro dropped 0.6 percent to 94.85 yen and touched 94.24 yen, the lowest since November 2000. The yen gained 0.2 percent to 78.36 per dollar.