South Korea's top intelligence agency has been receiving approval from the president every four months to legally monitor foreigners who could be spies or terrorists, a ruling party lawmaker said Tuesday.
  

The remarks came amid lingering controversy over hacking software programs the National Intelligence Service purchased from an Italian hacking firm in 2012.
  

The NIS emphasized that it used the programs to strengthen its cyber warfare capabilities against North Korea and only against people living outside the country that have ties with the reclusive, communist country.
  

Such an explanation, however, has been met with skepticism by many in the country, and in particular, the main opposition party, which believes the NIS has also spied on South Korean civilians.
  

The opposition New Politics Alliance for Democracy claimed that it is a clear violation of the law even if the NIS only uses the hacking program against North Korea if it does not have presidential approval.
  

"There is a list of potential foreigners working as spies for the North and terrorists," Lee Chul-woo, a lawmaker of the ruling Saenuri Party, said in an interview with a local radio station Tuesday.
  

The NIS official-turned-lawmaker said that monitoring their movement is not against the law as the NIS gets presidential approval.
  

The dispute has become more heated after an NIS employee was found dead in an apparent suicide in his car last week and left a suicide note denying the agency's involvement of illegally spying on citizens. (Yonhap)