Threshold of war on the Korean Peninsula! Seoul warns Pyongyang by firing on the border

The brink of war on the Korean Peninsula. South Korea's military fired toward the border with Pyongyang as a warning sign to repel North Korean soldiers who temporarily crossed the rivals' land border for the second time this month.

South Korea's military is closely monitoring North Korea's construction activities along their border to install anti-tank barriers, road reinforcement and the laying of land mines.

Work has continued unabated despite several explosions caused by mines that killed or injured an unspecified number of North Korean soldiers, senior South Korean military officials said.

According to South Korea's Joint Chiefs of Staff, about 20 to 30 North Korean soldiers, while engaged in unspecified construction work on the northern side of the border, briefly crossed the military demarcation line that separates the countries into two parts.

 The Korean soldiers retreated after the South warned them by firing gunfire.

The South also fired warning shots on June 11 after another group of North Korean soldiers briefly crossed the border. The Joint Chiefs of Staff said Tuesday's incident occurred in another area along the central frontline region.

He said he does not believe North Korean soldiers entered the border on purpose and that the North did not respond to South Korea's warning signs. The incident occurred as Russian President Vladimir Putin will visit North Korea for the first time in 24 years.