Kim Jong Il, who dictatorially ruled North Korea for 17 years, is dead at the age of 69. The official announcement appeared on North Korean state television this morning, with a dressed-in-black tearful presenter.

According to the official report, Kim Jong Il experienced a heart attack while he was on a train, during what it called a “field inspection.” The reports say every possible measure was taken to save his life, but that an examination on Sunday confirmed the cause of death. North Korean leader is said to have suffered a stroke earlier in 2008 as well, appearing visibly weak in a few of the photos that were released recently.

As far as North Korea is a Communist country, a system of hereditary succession is successfully maintained. Kim Jong Il had his leadership inherited from his father, Kim Il Sung, who passed away in 1994. Now the new leader will be Kim Jong Il’s youngest son Kim Jong Un, officially named as throne successor by his father in 2010.

The experts find the death of the dictator to be somewhat “surprising”, here is why: despite of being a sort of failed state, North Korea is also a dangerous one as long as it has the nuclear power. The unexpected death of the leader definitely produced deep worries, together with high uncertainty and instability as well. Not long after the announcement of Kim’s passing away, South Korean military is put on “high alert”, with the president Lee Myung-bak calling his national security council up.

As for the US, The White House has declared that President Barack Obama had been notified and U.S. officials are communicating with their South Korean and Japanese counterparts. Even China, believed to have as close relationships with North Korea as “lips and teeth”, is concerned about North Korean nuclear ambitions.