MADRID: Spain sold 5 billion euros ($6.5 billion) of short term debt on Tuesday at higher yields than a month ago, days ahead of a vote on Scottish independence that has unsettled some buyers of debt from countries with separatist movements.

Spain's wealthy Catalonia region wants to hold a referendum on Nov. 9 on separating from the rest of Spain, which government of Prime Minister Mariano Rajoy says would be illegal.

The Treasury had aimed to raise between 4 billion and 5 billion euros at the auction of six- and 12-month T-bills.

It sold 1.2 billion euros of six-month bills at an average yield of 0.111 percent, up from 0.080 percent at the last auction of the same maturity on August 19.

Demand was 2.4 times the offer amount, in line with the previous auction.

The Treasury sold 3.8 billion euros of the 12-month bill at an average yield of 0.219 percent, also higher from 0.160 percent at the last auction in August.

The bond was 1.8 times subscribed compared to 1.9 times previously.