Various companies from a cross section of industries have sought the assistance of the U.S. Department of Homeland Security in the wake of an onslaught of cyber burglaries that have plagued their computerized control systems.

The cyber-terrorists have resorted to more sophisticated schemes to break into automated structures, according to a senior official of the department.

A report from The Associated Press said that Acting Homeland Deputy Undersecretary Greg Schaffer has admitted that public utilities and industries all over the world are becoming more at risk when they connect their industrial equipment to the internet and global networks.

Schaffer hinted that professional hackers, discontented or terminated employees and even foreign governments as probably responsible for these incursions.

The U.S. government has already suggested to make reporting on the part of private companies compulsory but the political opposition is not inclined to impose more regulatory decrees on the private business sector.

Under the law, reporting of cyber attacks is made purely on a voluntary basis.

Homeland Security claims that the number of companies that solicited their assistance has reached 81 from just 57 in 2010.

The department's Computer Emergency Response Team for Industrial Systems has already responded to 7 incidents of attacks or exposure of their control processes.

So far, officials revealed that there has been one guilty verdict for the corruption of automated systems and this was the case of a former security guard in a hospital in Dallas who hacked the computers to close down the air-conditioning system. He was given a prison term of 9 years.

The department has a Cyber Analysis Center where the control systems are checked for exposure and a malware laboratory for evaluating cyber threats. It also houses a confidential "watch and warming" center that assesses statistics on threats and shares these figures with other intelligence and security agencies.

U.S. officials have expressed concern that there will be an escalation of cyber attacks on industries and possible targets include power plants, pipelines and air traffic control systems.

Cyber warfare would also likely target military facilities, communications, equipment and armaments.