Ukrainian President Viktor Yanukovych signed the law on national referendums on Tuesday, the president's Web site reported.

The Verkhovna Rada passed the bill on national referendums on November 6, 2012.

According to the document, a national referendum can be called to approve new wording of the constitution, amendments to it, and the cancellation of a law amending the constitution.

Referendums can also be called to decide on issues related to a change in the territory of Ukraine.

According the law, a national referendum can be initiated by the Ukrainian people and the Verkhovna Rada in the cases, and under the procedure foreseen by the constitution and laws.

A referendum may be called at request of at least 3 million Ukrainian citizens in more than two thirds of Ukraine's regions, and at least 100,000 signatures have to be collected in each of the regions.

The opposition stated that it would demand the cancellation of the document via the Constitutional Court of Ukraine if the Verkhovna Rada does not cancel it first. The opposition said that the adoption of the document would mean that after the parliamentary elections the Constitutional Assembly would draw up a bill amending the constitution and call a national referendum to approve new wording of the constitution. Thus, according to the opposition, the authorities may put to a referendum a law under which parliament will elect the president of Ukraine.