WASHINGTON (AP) — U.S. long-term mortgage rates fell this week to their lowest level in 13 weeks, as financial markets roiled by U.S.-Iran conflict pushed investors toward the safety of Treasury bonds.

The yield on Treasury bonds, especially the 10-year note, tends to influence mortgage rates. Mortgage buyer Freddie Mac said Thursday the average rate for a 30-year fixed-rate mortgage dropped to 3.64% from 3.72% last week. The benchmark rate was 4.45% a year ago.

The average rate on a 15-year mortgage declined to 3.07% from 3.16% last week. The historically low levels of borrowing rates are continuing to propel demand from prospective homebuyers.