TEHRAN, March 3 -- Iran stressed the peaceful nature of the country's nuclear activities ahead of another round of talks with world powers to pave way for a comprehensive agreement on its controversial nuclear drive.

Iran's nuclear program is undoubtedly peaceful and the West knows about it, Iranian President Hassan Rouhani was quoted as saying by Iran Daily on Monday.

"The International Atomic Energy Agency (IAEA) conducted thousands of hours of inspections in Iran's nuclear program and found no indication of diversion to weapons-grade activities," Rouhani said.

"All of them (Western powers) have no doubt that the nuclear science in this country follows a peaceful course," Rouhani said ahead of an expert-level meeting on the country's nuclear program.

On Monday, it was announced here that expert-level nuclear talks to discuss the details of a possible comprehensive agreement on Iran' s nuclear issue will start in the Austrian capital Vienna on Wednesday.

The talks, which follow a senior-level meeting in February, will last for three days until Friday, said Hamid Baeidinejad, the director general for political and international affairs at Iran's Foreign Ministry, who also heads Iran's expert-level nuclear negotiating team.

The delegation from the P5+1 group -- Britain, China, France, Russia, the United States plus Germany -- would be led by Stephen Clement, an aide to EU High Representative for Foreign Affairs and Security Policy Catherine Ashton, Baeidinejad said according to Iran's Press TV.

Tehran is a signatory to Non-Proliferation Treaty (NPT) and has not violated it, Rouhani said.

"If Iran was after producing weapons of mass destruction (WMDs), it was easier to build chemical and biological arms," he said, adding that building WMDs has not been in Iran's defensive doctrine and his country considers making them as its "red line."