The European Central Bank bought no government bonds last week, suggesting the programme has effectively been shut down after euro zone leaders agreed to give its bail-out fund the power to buy debt.

Comments from ECB policymakers point to the programme having been wound up, despite the debt crisis in the euro zone showing signs of infecting Italy and Spain.

Government leaders agreed last Thursday on a second rescue package for Greece in a deal which includes the right for the European Financial Stability Facility (EFSF) to buy bonds on the secondary market at the ECB's recommendation.

But the EFSF's ability to buy bonds is limited by its €440 billion capacity, which means the ECB may want to keep its bond-buying programme on the backburner instead of officially shutting it down. The ECB has not announced any limits to its programme, and can also act quickly.

Yields on peripheral euro zone government bonds have come down after the deal for the Greek second rescue package, but remain high on doubts about whether the steps taken last week to ring-fence the euro zone crisis went far enough. The yield on 10-year Spanish bonds was over 6% this evening, while the Italian equivalent rose to 5.66%.

The ECB started its bond purchases May last year as part of euro zone efforts to stave off the debt crisis. It and the 17 euro zone national central banks can buy government and corporate bonds from banks and other investors under the programme, but not directly from governments.

The ECB does not break down its bond purchases, but traders and analysts say buying has been limited to Greek, Irish and Portuguese bonds and estimate that it holds around €45 billion of Greek debt.