WASHINGTON — Average long-term U.S. mortgage rates rose this week to the highest level since mid-March.

Mortgage giant Freddie Mac said Thursday that the national average for a 30-year fixed-rate mortgage rose to 3.80 percent, from 3.68 percent last week.

The rate on 15-year fixed-rate mortgages averaged 3.02 percent, up from 2.94 percent. It’s the first time the 15-year rate has topped 3 percent since it hit 3.06 percent in mid-March.

A year ago, the average 30-year rate stood at 4.21 percent and the 15-year at 3.32 percent. The 30-year average rate hit a record low 3.31 percent in November 2012.