The Crime branch, investigating the serial blasts, which rocked the city on July 26, has carried out massive combing operations in various areas even as several people have been detained for questioning, the police said on Thursday. 

"Massive combing operations were conducted by different teams in various parts of the city last night. Several people have been detained for questioning. However, reports from all the teams are yet to be consolidated," Joint Commissioner of Police H P Singh said.

Meanwhile, the Bharuch district police received a hoax call this morning which said that explosives were found in Ankleshwar area of the city.

However, when the bomb and dog squads examined the substance on the spot, no explosives were found.

Teams of Central Intelligence Bureau (CBI), police teams of Mumbai, Hyderabad, Rajashtan, Uttar Pradesh [Images] and Delhi [Images] are in Gujarat to assist the state police in probing the blasts that claimed 53 lives and injured over 140 people.

Also, the city Crime branch has sent a team of officials to Navi Mumbai after the cars used in Ahmedabad [Images] serial blasts and e-mail received in this case were traced to that area.

Yesterday, the Bharuch district police detained ten people, who were earlier associated with SIMI [Images], for questioning.

So far, the only significant breakthrough in the serial blasts case has been the arrest of SIMI activist Abdul Halim from the Dani Limbda area of the city during a combing operation.

Halim has been remanded to police custody till August 10 and is being interrogated the crime branch officials.

The city crime branch had also interrogated certain cycle shop owners and traders from the Dani Limbda area to nab suspicious buyers, who might have purchased bicycles from their shops.

Police is also focusing on the Vadodara angle for investigations, as the fake number plates found on all the cars used in terror attacks had Vadodara passing.

Besides, an email threat had forced the M S University authorities to close all the colleges in the city yesterday.

Meanwhile, the state government has formed a special committee to enable coordination between investigating agencies of Gujarat and that of other states and Centre.