Shillong/Imphal, January 23 (TIWN / IANS) A massive security alert has been sounded across northeast India after separatist rebels announced a boycott of the Republic Day celebrations Jan 26, a home ministry official said Friday. "We are aware that they (rebels) will be making attempts to disrupt the Republic Day celebrations. Therefore, we have placed security forces on high alert to thwart the rebels from disrupting the celebrations," Shambhu Singh, joint secretary (northeast) in the home ministry, told IANS by phone from New Delhi.Four frontline separatist groups in the region have called for a boycott of Republic Day and also a general strike from 9 p.m. Jan 25 to 6 p.m. Jan 26.Rebel groups in the northeast have for years boycotted national events and have staged violent attacks in the run-up to the celebrations."We are on full alert and shall see to it that we are able to foil any attempts by rebels to attack," an Assam Rifles official said.

There has been a string of bomb blasts in Manipur triggered by rebels.

The four rebel groups announced their boycott through a joint statement e-mailed to several media houses.

The call has been given by the United Liberation Front of Asom (ULFA), the National Democratic Front of Bodoland (NDFB), the Kamatapur Liberation Organisation and Coordination Committee (CorCom) - an umbrella organisation of major separatist outfits fighting for an independent state for the majority Metei community in Manipur.

Moreover, the outlawed Hynniewtrep National Liberation Council has also called for a 24-hour shutdown from 6 p.m. Jan 25 to 6 p.m. Jan 26 across the six districts of Khasi-Jaintia hills region in the eastern part of Meghalaya.

Thousands of army, police and paramilitary troopers are standing guard in other northeastern states to ensure that militants are not able to indulge in violence ahead of the Republic Day celebrations, particularly in Manipur.

"Flushing out operations are on to nab the rebels who are attempting to disrupt the Republic Day celebrations. The police across Manipur have been put on high alert and we are determined to thwart any subversive activity by the militants," Manipur's Inspector General of Police Clay Khongsai told IANS.

Rebel groups often target vital infrastructure like road and rail bridges, oil installations and security forces.