Turkish Prime Minister Recep Tayyip Erdogan has criticised the tactics of his political opponents ahead of a referendum on constitutional reform.
Speaking to the BBC ahead of Sunday's vote, Mr Erdogan accused them of using "disinformation and black propaganda".
The proposed reforms include controversial changes to the judiciary.
A positive result is expected to help the country in its bid to join the EU, by finally dissociating it from remnants of autocratic rule.
The present constitution was introduced in 1982 by the military. Significant amendments have been made to it since then, but this is the first time it has been put to a referendum.
The EU has said it sees the vote as a significant step for Turkey's democratisation and modernisation.
Opposition parties say the new changes will give the government more control over the appointment of senior judges.
In a speech on Wednesday, Republican People's Party (CHP) leader Kemal Kilicdaroglu said Mr Erdogan was trying to seize the judiciary.
He said Mr Erdogan "lamented" being able to appoint the president, the parliamentary speaker, governors and chiefs of police, but not a single judge.
"'Give me the authority, Erdogan says, so that I can also appoint judges," Mr Kilicdaroglu said.
The BBC's Jonathan Head in Istanbul says a "no" vote or only a marginal win would be seen as a blow to Mr Erdogan, who has dominated Turkish politics for the past eight years following two decisive election victories.
Opinion polls suggest the vote will be close.
Mr Erdogan has been travelling around Turkey for the past three weeks, trying to drum up support for his reforms.
But he told the BBC the main opposition parties were deceiving voters.
"At the moment, there is a flood of disinformation and black propaganda," he said.
"They claim these reforms are my personal project or a project of my party - that claim is unfounded."
Mr Erdogan argues the reforms will make the military-drafted constitution more democratic.
However, his critics have accused his ruling Justice and Development Party (AKP) of trying to seize control of the judiciary as part of a back-door Islamist coup.
The AKP has clashed repeatedly with Turkey's highest courts, which see themselves as guardians of the country's secular values.
But Mr Erdogan told the BBC his party had never discriminated between secular or non-secular Turks.
"We have brought services to all regions, all classes and all ethnic groups, without any discrimination," he said.
"From a wider perspective we are the real democracy in this region and as a democratic country we always want to do better, so with these reforms I will bring in a more progressive democracy to our country."
He said he believed that secularism should apply to the state, not the people.
"As in any country, in Turkey religion is an important factor in political life. Trying to avoid this reality will lead to the destruction of that society," he said.