Close on the heels of the arrest of two Pakistani trained terrorists in Lucknow on Thursday, Uttar Pradesh Special Task Force nabbed two Inter Services Intelligence agents from yet another locality in Lucknow in the wee hours of Saturday.

STF sleuths recovered one AK-47 rifle, a Chinese pistol, about 9 kg of RDX, besides a large quantity of ammunition from their possession.

The arrests have led the UP administration to declare a red alert throughout the state.

"We have reason to believe that UP is on ISI's latest target so we need to take necessary precautionary measures," a top official of the state home department told this scribe.

One of the arrested was described as a "very big catch." According to a STF spokesman, 40-year old Babu Bhai , intercepted by us near the Residency in Lucknow on early Saturday morning was one of the top ISI agents in the country."

"A resident of Kolkata, Babu Bhai was believed to be heading a major Harkat-ul-Jihad Al Islam module detailed to carry out a series of blasts during the forthcoming 'sawan melas' in different key pilgrimage centres of the state," he said.

The 'melas' draw huge rural crowds particularly at Varanasi, Ayodhya and Garh Mukhteshwar.

The other arrested man was identified as Naushad, who hails from Bijnore and had been selected by Babu Bhai to carry out certain ISI missions in the state.

"Like the two HUJI activists arrested on Thursday, Naushad too had received training in ISI camps in Pakistan," the spokesman said.