Lawmakers in the United States have introduced a bill proposing that North Korea be relisted as a state sponsor of terrorism, Yonhap News Agency reported Sunday. The bill, submitted to the U.S. House of Representatives, detailed over 20 cases linking the reclusive state with possible terrorist acts.

The findings also include the 1987 bombing of Korean Air Flight 858 by North Korean agents and the December 2014 cyberattack on Sony Pictures Entertainment. The bill calls for a review of the cases and the submission of a report to Congress on whether the Asian nation can be defined as a sponsor of terrorism. The government will also have to submit an explanation as to why North Korea cannot be put on the list, if the administration decides against the proposal.

“It is the sense of the Congress that North Korea meets the criteria for designation as a state sponsor of terrorism and should be so designated,” the bill, introduced May 12, read.

Pyongyang was designated a state sponsor of terrorism on Jan. 20, 1988, after the bombing of Flight 858, which killed all 115 people aboard. However, in 2008, then President George W. Bush’s administration removed North Korea from the list after the East Asian country agreed to dismantle its nuclear weapons program.

The introduction of the bill last week came after North Korea concluded its much-hyped seventh congress, a gathering of the country’s governing elite earlier this month. The country also faces strict sanctions from the United Nations Security Council over its fourth nuclear test in January and a rocket launch in February.

Meanwhile, the U.S., South Korea and Japan are expected to perform their first joint military training June 28 to detect signs of missile launches from North Korea. The South Korean defense ministry said the drills will involve Aegis-equipped ships from each of the three countries, the Associated Press reported. However, the exercises will not involve missile-interception training.

The Kim Jong Un-led regime has conducted a series of missile and nuclear tests since the beginning of this year, and the leader has called for a strengthening of the country’s defense capabilities. Pyongyang has also claimed to have secured intercontinental ballistic missile technologies.

Last month, North Korean Foreign Minister Ri Su Yong said that his country will halt nuclear tests if the U.S. stops annual military drills with South Korea, an offer that was dismissed by U.S. President Barack Obama.