Velásquez made his debut for El Salvador in a May 1999 friendly match against Colombia and has earned a total of 54 caps, scoring 4 goals. He has represented his country in 10 FIFA World Cup qualification matches and played at the 2001, 2003, 2005 and 2007 UNCAF Nations Cups as well as at the 2002 and 2003 CONCACAF Gold Cups.