New Delhi, Apr 16 (IANS): Left-wing extremism, religious fundamentalism, ethnic violence and terrorism are major challenges facing the country, Prime Minister Manmohan Singh said here Monday and urged states to fight these together with the central government.

"Left-wing extremism, religious fundamentalism, ethnic violence and terrorism are the major internal security challenges facing the country... I urge the states to fight them together with the centre," Manmohan Singh said while inaugurating the annual conference of chief ministers on internal security here.

"The internal security situation in the country since February 2011 has been by and large satisfactory," he said.

The situation concerning left-wing extremism was better in 2011 than in 2010 but there was still a "long way to go", the prime minister observed.

He said the number of districts under the integrated action plan to push development has been increased from 60 to 78 across seven states affected by Maoist violence.

Union Home Minister P. Chidambaram, who spoke before the prime minister, also described left-wing extremism as the most formidable security challenge facing the country.

Stating that India needs to strengthen its defences against terrorism, the prime minister said this was necessary keeping in mind the growing instability around the country.

"Today, terrorist groups are nimble, more lethal than ever before and increasingly networked across frontiers," said Singh.

Chidambaram said India's international border and the Line of Control in the western sector "are vulnerable to infiltrations".

Noting a perceptible improvement in the law and order situation in the border state of Jammu and Kashmir, the prime minister expressed concern that the situation in some of the northeastern states has remained complex.

"The pilferage of development funds by militant groups is hurting our efforts to improve the lives of the people of the region. Inter-factional clashes, such as those in Tirap and Changlang, are another source of insecurity," said Singh.

He expressed satisfaction over the political processes of negotiation and dialogue under way with several insurgent and ethnic separatist groups in the northeast.

Laying stress on police modernisation, the coastal security scheme and the border area development programme, the prime minister urged the states to carry forward these plans while working on ways and means to improve the quality of personnel to make the country safer.