A militant was on Tuesday arrested in South Delhi and 2.5 kg RDX was seized from his possession, police said.

Aijaz Hussain, hailing from Baramulla district of Jammu and Kashmir [Images], was arrested from Lodhi Road area after police received a tip-off about his movement, Delhi's Deputy Commissioner of Police (Special Cell) Alok Kumar said.

Police was interrogating him to find out if he has any links with the serial blasts in Srinagar [Images] and Mumbai and to find which terrorist outfit he belonged to, he said.

An amount of Rs 49 lakh (Rs 4.9 million) was also seized from him, police said, adding that according to their information Hussain was working for one Pakistan-based militant Mukhtar Ahmed. Hussian, who has been living in Jangpura locality of South Delhi, was arrested when he reached the Lodhi Road area in a car to apparently hand over the cash and explosives to someone.

Police, meanwhile, has stepped up security and checking in and around the national capital in the wake of blasts in Mumbai and Srinagar. They are also conducting random searches in hotels and lodges.

63 killed in 7 blasts in Mumbai suburban trains