NEW YORK (CNN/Money) - Mortgage rates swung higher in the latest week after reaching record lows last week as the Iraqi conflict led to a rise in bond market yields, Freddie Mac said Thursday.

The 30-year mortgage averaged 5.79 percent for the week ending March 21, with an average of 0.6 of a point payable up front to the lender, up slightly from a record low of 5.61 percent last week, according to the lender.

Last year at this time, the long-term mortgage rate stood at 7.14 percent.

The 15-year fixed-rate mortgage also rose higher, averaging 5.11 percent, significantly higher than last week's record low of 4.93 percent. The 15-year rate averaged 6.6 percent one year ago.

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One-year adjustable-rate mortgages (ARMs), loosely indexed to the 10-year Treasury note, averaged 3.75 percent, up from the record low 3.68 percent the previous week. The one-year average stood at 5.11 percent for the same week last year.

"Lack of uncertainty around the Iraq conflict caused bond market yields to reverse their downward spiral of recent weeks and mortgage rates followed in tandem," said Frank Nothaft, Freddie Mac chief economist. "But there are other uncertainties about the length of the conflict and its impact on the economy that will influence mortgage rates in the weeks to come, so this rise in rates may be only temporary."

Freddie Mac's average mortgage rates are based on a survey of 125 lenders nationwide. The rates include those on mortgages accepted by borrowers with good credit ratings who place a 20 percent down payment on their homes, according to Freddie Mac. The total amount of each mortgage considered for the survey doesn't exceed a $300,700 limit.

Freddie Mac (FRE: down $1.40 to $54.02, Research, Estimates), or Federal Home Loan Mortgage Corp., is a publicly-traded company the government established in 1970 to provide a flow of funds to mortgage lenders. It buys mortgages from banks, bundles them and then resells them as mortgage-backed securities.

Its products, and the products of other similar entities, have become increasingly popular as an alternative to government-backed bonds, particularly with international investors.