WASHINGTON — Interest rates on short-term Treasury bills rose in Monday’s auction with rates on six-month bills climbing to the highest level in three weeks.

The Treasury Department auctioned $32 billion in three-month bills at a discount rate of 0.100 percent, up from 0.09 percent last week. Another $28 billion in six-month bills was auctioned at a discount rate of 0.145 percent, up from 0.135 percent last week.