BRUSSELS: Belgium's borrowing costs dropped to a record low on Monday at a 2 billion euro ($2.6 billion) sale of its 10- and 20-year benchmark bonds, the debt agency said on Monday.

The 10-year benchmark bond, with a 2.60 percent coupon, sold for a yield of 1.284 percent, down from 1.547 percent at a July auction which was already a record low for the maturity.

Investors took a yield of 2.214 percent for the 3.00 percent 20-year bond , also down from the 2.639 percent when this OLO was first issued in January.

With 26.566 billion euros of long- and medium-term bonds sold, Belgium has now raised some 88.55 percent of its 30 billion target for 2014, with two more auctions planned.

The debt agency said it was unlikely to raise this target, as it has often done in the past to pre-fund the following year's requirement as well as to shift from shorter-term bills to longer-term bonds.

The average maturity of the kingdom's debt is 7.7 years, the debt agency said.

The AA-rated sovereign had set a target range of 1.5 to 2.0 billion euros for Monday's auction. At 2.006 billion euros, it was the second smallest auction this year.