Azerbaijan's parliament, in a vote on the eve of a referendum on constitutional amendments, has approved a mass amnesty bill that will affect thousands of prisoners.

The bill, passed Tuesday, covers some 9,000 prisoners, including those convicted of non-violent crimes, inmates under the age of 18, over the age of 60, as well as prisoners serving the last year of their sentences.

The country's first lady, Mehriban Aliyev, a member of parliament, proposed the bill.

The move comes ahead of Wednesday's controversial constitution referendum that will include a measure removing presidential term limits.

On Monday, the Council of Europe asked Azerbaijan to postpone the vote saying that if passed, the constitution would not conform to European democratic standards.

The referendum would add 29 amendments to the constitution, including one that imposes more central government control over local governments.

Opponents of Azerbaijani President Ilham Aliyev are boycotting the vote.

The president's critics insist that lifting term limits will essentially make Mr. Aliyev president for life. Opponents also have accused the United States and Europe of ignoring recent political and media restrictions imposed by the Aliyev government, for fear of losing access to the country's vast energy reserves.

Some information for this report was provided by AFP, AP and Reuters.