In the wake of these threats, US has issued an advisory to its citizens and diplomats in India advising them to be cautious.
Home ministry officials have been holding regular meetings with Delhi Police and Intelligence Bureau on the terror threats.
Sources say that IM or Lashkar may take help of sleeper cells to carry out serial bombings.
Religious places, government buildings and Metro stations are also on the target of terror groups, officials said, adding they have specific inputs about infiltration but refused to give details due to security reasons.
The terrorists in Pakistan are being already given army level training with the help of Pakistan's official agencies, as recently revealed by Yasin Bhatkal as well.
For the Republic Day, there will be a three-tier security in Delhi comprising the army, the paramilitary and the Delhi Police.
Paramilitary troops have been positioned in central Delhi, along the Rajpath where President Pranab Mukherjee will unfurl the Tricolour and take the salute of the marching contingents.
The specialized units like Special Cell and Crime Branch have also been roped in to thwart any attempt by the terrorists to spread terror.
