Pangyo: No bomb was found following a threat at the headquarters of messenger app operator Kakao Corp. in Pangyo, south of Seoul, on Monday, police said. The Bundang Police Station said it conducted a search of the building and its surroundings by deploying around 70 personnel. No suspicious items were discovered.

According to Yonhap News Agency, earlier in the day, Kakao reported to the police the bomb threat, which came through the company's customer service center at 11:09 a.m. "As we prioritize employee safety above all else, we transitioned all staff to work remotely," an official from Kakao said.

The suspect reportedly wrote on Kakao's customer service board twice earlier in the day that a self-made explosive device had been placed in the company's office. The suspect is said to have also threatened to kill high-level company officials with a homemade gun and demanded the company send 10 billion won (US$6.8 million) to a bank account, according to officials from Kakao and the police.

Kakao earlier instructed all employees to work from home. After concluding that there were no explosives or other safety threats, police lifted the building lockdown and allowed normal access. Kakao said all of its employees are expected to return to work as usual Tuesday.

The bomb threat came in light of massive user backlash following its biggest overhaul of the messaging app in 15 years. According to industry sources, Kakao plans to revert its Friends tab to the previous version, which lists contacts in alphabetical order, from the current grid-style feed similar to Instagram.

The move comes nearly three months after the company announced a redesign of the Friends tab into an Instagram-like feed, a change that triggered widespread user complaints and sent its stock price tumbling. The update is expected to take place sometime this week, with users given the option to choose between the previous version and the Instagram-like feed style, the sources said.