NEW DELHI, July 27: The diamond city of Surat in the western Indian state of Gujarat was put under the security scanner on Sunday after two cars were found there stuffed with explosives, officials said.

They said a live bomb was defused and an activist of the outlawed Muslim extremist Simi group was arrested in connection with Saturday’s serial blasts in Ahmedabad where the death toll mounted to 49.

Press Trust of India said a live bomb was defused near a hospital and two cars stuffed with explosives were found in the city on Sunday, sparking a high security alert.

The Simi activist, identified as Abdul Halim and wanted in connection with the 2002 violence in Gujarat, was arrested from the communally sensitive Dani Limda area of Ahmedabad. He had remained elusive since the carnage though it was not clear what charges were slapped on him.

Anti-Terrorist Squad early on Sunday raided two flats in Mumbai after the Internet Protocol (IP) address of the sender of an e-mail warning about Ahmedabad blasts was traced to it.

The sender was tracked to a flat in Gunina Apartments in Sanpara near Navi Mumbai. The flats are registered in the name of someone named Abhishek, but rented to two foreign nationals who work for a multinational company. The flat was rented out about five months ago.

Army-led flag marches were carried out in vulnerable parts of the city to instil confidence among its shaken residents.

In New Delhi, Home Minister Shivraj Patil chaired a high-level meeting to review the security scenario in the country in the wake of the Ahmedabad blasts and assured all possible help to the BJP government in Gujarat in its hour of crisis.

Prime Minister Manmohan Singh and UPA Chairperson Sonia Gandhi will visit Ahmedabad on Monday to have an assessment of the situation in the wake of the serial blasts in the city and visit hospitals where the injured are undergoing treatment.

Senior BJP leader L.K. Advani, who is a Lok Sabha member from Gujarat, visited the wounded in the city’s civil hospital and demanded revival of tough anti-terror laws like Pota, saying existing laws are ineffective.

He also took the opportunity to attack the UPA government, saying it did not appear to be adopting zero tolerance towards terrorism. He gave the example of the delay in the execution of parliamentary attack convict Afzal Guru.

Several states, including Uttar Pradesh, Madhya Pradesh, Delhi, Himachal Pradesh and Uttarakhand, sounded red alerts, stepping up security in sensitive areas.