Prime Minister Atal Bihari Vajpayee on Wednesday said terrorism posed a big threat to global peace and asked parliamentarians the world over to strengthen mutual cooperation to combat the menace.

"How can parliamentarians strengthen mutual cooperation in the fight against terrorism and extremism, which have become a big threat to peace, democracy and civilised world order?" he asked while addressing the opening session of the three-day International Parliamentary Conference being held in New Delhi to mark the golden jubilee of Indian Parliament.

Vajpayee asked whether parliaments should be allowed to run their full term and if there were ways to ensure stability of governance and policies while retaining the vibrancy of a multi-party democracy.

Asserting that in a democracy there were bound to be differences among political parties, the prime minister said the vitality of democracy also demanded discipline, constructive approach and readiness to contribute to consensus-building on pressing issues.

The conference is likely to discuss four themes -- terrorism, parliamentary practices and procedures and the need for reform to secure greater executive accountability, parliament as a vehicle of social change and parliament in the era of globalisation and liberalisation.

Observing that in several countries important decisions remained pending as some or the other election is taking place all the time, the prime minister wanted an opinion from legislators whether elections should be scheduled for all tiers simultaneously.

President A P J Abdul Kalam, Vice President Bhairon Singh Sekhawat, Lok Sabha Speaker Manohar Joshi, former presidents R Venkataraman and K R Narayanan, former prime ministers P V Narasimha Rao and I K Gujral, Leader of the Opposition Sonia Gandhi, Cabinet ministers and members of Parliament attended the inaugural function in the Central Hall of Parliament.

Underlining that the golden jubilee of Indian Parliament was an "important milestone" in the onward march of democracy worldwide, Vajpayee said: "Democracy is that system in which there can be opposition without hatred and power can change hands without resorting to violence. It disallows discrimination on any ground. In this sense, democracy has deep roots in India's national ethos and our ancient culture, which teach respect for divergent and even dissenting points of view," he said.

"If the 20th century saw the global growth of democracy, the new century should see its further expansion and enrichment. We should develop democracy as an effective instrument for fulfilling people's aspirations and resolving conflicts and contentious issues," Vajpayee said.

The prime minister said history had proved time and again that free and democratic societies were the ones that were creative, self-corrective and self-regenerative.

"Holding of regular elections, the victories and defeats of individuals and parties, and periodic change of governments have many benefits," he said.