Negative opinions of South Korea appear to be increasing in North Korea, a study on defectors showed on Wednesday, apparently reflecting last year’s elevated tensions on the Korean Peninsula.

A June poll conducted by Seoul National University’s Institute for Peace and Unification Studies showed 55.7 percent of surveyed defectors said they had thought of the South as a cooperative partner while living in the North, down from 63 percent last year. The IPUS polled 149 defectors who left the North in 2013 and entered the South this year.

Defectors who said they had thought the South was a hostile nation increased to 20.1 percent this year, up from 12.8 percent.

The survey results may reflect the aftereffects of heightened tensions between the two Koreas early last year, according to experts.

“Last year’s tensions and Pyongyang’s lengthened internal propaganda campaign could have influenced the North Korean populace,” Kim Philo, a professor at the IPUS, told local media on Wednesday.

North Korea conducted its third nuclear weapons test in February 2013. Seoul criticized the move and went ahead with annual joint defense exercises with the U.S. in March. In April, North Korea unilaterally shut down the Gaeseong industrial park, a joint enterprise between the two Koreas.

But it could be inaccurate to conclude that South Korea’s image in the North worsened during the past year, an experienced pollster said.

“The sample pool is too small to conclusively say there had been a general change of attitude among North Koreans,” Heo Jin-jae, a senior researcher at Gallup Korea, said.

“Usually, the margin of error for a sample pool of 1,000 is around 3 percent. If the pool is 149, there is going to be a larger margin of error.”

An 8 percent change from last year’s results is a bit weak for reaching such a conclusion, Heo said.

Inter-Korean relations remain fragile. North Korea has criticized the annual Ulchi Freedom Guardian military exercises that the South and the U.S. kicked off last week. Pyongyang officials call the exercises a rehearsal for war, while Seoul and Washington officials call the training defensive in nature.

By Jeong Hunny (hj257@heraldcorp.com)