The anti-government "red-shirt" clad group is actively forming an underground movement across the country, according to intelligence reports, which have been gathered following the dispersal of the "red shirt" gathering, Special Branch chief Pol Lt-General Treethos Ronnaritwichai said on Thursday, the Komchadluek newspaper's online.

Pol Lt-General Treethos refused to provide details concerning the renewed anti-government movement on concerns that it might negatively affect police's operations and attempt to contain their movement.

However, a special task force has been formed to closely monitor their movement throughout the country, Pol Lt-General Treethos said.

The "red-shirt" protesters had occupied the Rajaprasong Intersection, the main commercial area in central Bangkok, since early April before they ended their prolonged rally at 13:00 hours on May 19.

The death toll from a series of violent clashes between the anti-government protesters and troops during March 12 to May 19 stood at 88 as some 1,885 others were wounded, Public Health Minister Jurin Laksanawisit said on May 25.