NEW YORK, April 14 (Xinhua) -- The USA Swimming announced Monday that Olympic multi-gold medallist Michael Phelps will compete at a competition later this month after 20-month retirement.

The 18-time gold medallist, 28, will compete an event on USA Swimming's 2013-14 Arena Grand Prix Series on April 24-26 in Mexa, Arizona, the USA Swimming said.

This will be the first competition for Phelps after he won six medals, including four gold, at the 2012 London Olympic Games.