Mortgage applications declined 5% last week as interest rates spiked across the United States, an industry trade group said Wednesday. The slowdown follows a week of robust activity, with mortgage applications rising more than 15% a week earlier on increased refinacing activity. The Mortgage Bankers Association said its market composite index, a measure of loan mortgage application volume, dropped 5% on a seasonally adjusted basis and 4.9% on an unadjusted basis when compared to a week earlier. The refinance index and the seasonally adjusted purchase index fell 5.5% and 3.8%, respectively, from a week ago, while the unadjusted purchase index declined 3.4%. The four-week moving average for the purchase index dropped 0.5% this past week, while the four-week moving averages for the refinance index and market index declined by 0.3% each. Refinance activity made up 69.6% of total application volume, down from 70% a week prior. The interest rates for a 30-year, fixed-rate mortgage rose to 4.57% last week from 4.54% a week earlier. The average 15-year, fixed-rate mortgage increased slightly to 3.67% from 3.66%. Write to Kerri Panchuk.