Describing as "worrisome" the activities of externally-sponsored terror groups, Prime Minister Manmohan Singh today warned of a possible spurt in suicide attacks targetting religious, economic and sensitive institutions in the country.He termed as "disconcerting" reports that suggest the existence of a number of terrorist modules and sleeper cells in some urban areas, which provide the back-up for foreign terrorist outfits."The concern is that there could be a further intensification involving greater use of fidayeen elements, and targetting of a wider range of religious, economic and sensitive objects," Singh said addressing the two-day conclave of Chief Ministers of Congress-ruled states."Intelligence is clearly the key to better performance. Improvements in intelligence are being effected at the central and state levels," he said while asking the Chief Ministers to tone up their intelligence machinery.Emphasing on the importance of generating intelligence at the police station level, the Prime Minister pointed out that this area had not got the desired attention."There is no substitute for adequately trained and equipped police force and intelligence agencies. I am afraid this does not get the desired attention," he said."You need to look into this," he told the Chief Ministers attending the conclave.