To check rampant use of ammonium nitrate by terror groups, the Union home ministry on Tuesday discussed in detail certain amendments in the Explosives Substances Act.

The objective behind carrying out changes in the Act is to regulate use of the material often used in bombs by bringing ammonium nitrate under the purview of the existing law, a senior official said.

Tuesday's meeting of a working group formed in the wake of recent serial blasts in the national capital was chaired by Home Secretary Madhukar Gupta.

The group was mandated to frame elaborate rules under the Act to strengthen the framework for regulating manufacture, storage, transport and sale of explosives.

The meeting also discussed measures to strengthen administration and vigilance at the state-level and need to increase awareness among enforcement agencies in the states.

In this connection, a workshop of state police chiefs will be held soon.

The "in-principle" approval for amendment of the Explosives Substances Act has already been given by the Union Cabinet at its special meeting in the aftermath of the Delhi blasts.

Ammonium nitrate is believed to have been used in recent series of explosions in Bangalore, Ahmedabad and Delhi [Images] and in many earlier blasts carried out including the serial train blasts in Mumbai, Malegaon and Mecca Masjid.

Security agencies have long been pressing for bringing a strong controlling regime to check misuse of the chemical especially in Naxal-affected states.

An official release said the meeting was attended by the revenue secretary and officers of the ministries of industry and defence, Intelligence Bureau and the Petroleum and Explosives Substances Organisation.

The meeting discussed recommendations of the sub-group which had been set up at the level of joint secretaries of the concerned ministries to examine the existing legal and administrative framework, it said.

Home ministry sources said some suggestions have already been given to states to check use and trading of ammonium nitrate, which is commonly used as a fertiliser.

They said a strong controlling regime was needed to monitor the misuse of the chemical and ensure that offenders were booked under the Act.

The ministry feels that primarily it is the responsibility of transport, police and revenue authorities of the state governments to ensure that it does not land into wrong hands.

However, there was a laxity on part of these wings as ammonium nitrate continued to be smuggled out especially from quarries in Andhra Pradesh.

Ammonium nitrate is also a key component for manufacturing deadly RDX explosive. Though it is not a high-quality explosive like RDX, it can be used as a low-cost high-impact bomb by intelligent use of shrapnel, packing and proper fuel mix like diesel.