Imphal, Jan 23 (IANS): Security has been tightened in all the eight northeastern states for the upcoming Republic Day celebrations on Thursday.

In Imphal, 62 contingents representing state and central forces, government offices, educational, cultural and sports institutions, took part in a practice march past on Monday.

Police and paramilitary personnel have stepped up security in and around Manipur's capital city.

The police has also launched combing operations. Those who are found without proper identification papers will be taken to police stations for further verification.

Some members of the National Socialist Council of Nagaland- Isak-Muivah (NSCN-IM) rebel groups were arrested on Sunday including four who were caught with explosives.

The long border with Myanmar was virtually sealed to ensure that insurgents do not infiltrate into some of the states.

Meanwhile, the Chief Ministers of Assam and Arunachal Pradesh, Sarbananda Sonawal and Pema Khandu respectively, have slammed the killings of two Assam Rifles personnel on Sunday.

The personnel hailing from Manipur and Arunachal Pradesh were killed along the Assam-Arunachal Pradesh border.