North Korea has stepped up its campaign to block information on pro-democracy protests in the Arab world for fear of disturbances among its own people, South Korea's spy chief said on Friday.
"North Korea, fearing an inflow of such news, has been strengthening ideological indoctrination through its media," legislators quoted Won Sei-Hoon as telling a closed meeting of parliament's intelligence committee.
"It has stepped up a clampdown on outside information to prevent public disturbances," the National Intelligence Service chief was quoted as saying.
The hardline communist state tightly controls access to the Internet and attempts to block other sources of information about the outside world. But DVDs and mobile phones smuggled from China have been eroding barriers.
A survey by two US academics of some 1,600 refugees from the North found that roughly half of them had access to foreign news or entertainment.
However, most analysts discount the possibility of an uprising, given the absence of Internet access and a lack of institutions around which any revolt could coalesce.
Won, citing ongoing US and South Korean military exercises, did not rule out fresh attacks by the North.
"A North Korean attack is always possible," he was quoted as saying. "If it does, we will do our best to minimise damage as soon as possible."
The North's military calls the joint drills a rehearsal for invasion and has threatened to turn Seoul into a "sea of flames" in case of any provocation.
The exercises follow a year of high tensions.
The South accuses the North of torpedoing a warship in March 2010 near the disputed Yellow Sea border with the loss of 46 lives, a charge it denies.
Last November the North shelled a South Korean island near the border, killing two marines and two civilians.