New Delhi, Feb 7 (IANS) United efforts are needed to fight terrorists, Maoists and communal forces that pose "major threats" to our internal security, Prime Minister Manmohan Singh said Sunday as he asked the state and central governments to face the challenge with firm determination.

"Utmost vigil, sustained and coordinated efforts of the central and state governments are needed. We must periodically review the systems that are in place and ensure the safety and security of our country and our citizens," Manmohan Singh said while inaugurating the internal security conclave for state chief ministers held here.

The prime minister listed terrorism in Jammu and Kashmir and the northeast, Maoist insurgency in tribal-dominated central India and communal forces as "major threats" to the country.

"All of you are aware of the major threats to our security. Hostile groups and elements operate from across the border to perpetrate terrorist acts in our country. The state of Jammu and Kashmir bears the brunt of the acts of these groups.

"There is insurgency and violence in the northeast. Many states are affected by the Leftwing extremism, which I have in the past referred to as the greatest threat to our security.

The prime minister noted that there are also people "who try to divide our society on communal and regional lines".

"Each one of these threats require a firm determination and continuous vigil to tackle them. These threats to our society and people constitute a challenge that we shall and must meet at all costs," he said.