Reports of unidentified packages are continuing nationwide Friday, the day after three people suffered from dizzy spells after opening a suspicious international package. Authorities are collecting packages from several cities, and about 1,700 people have been evacuated at the Seoul Central Post Office in Myeong-dong, after a similar package was found.

The authorities are now investigating the possibility of terrorism, and as reports of related suspected cases continued, the Korea Post decided to temporarily suspend the import of similar types of packages from abroad.

According to police and fire authorities, an international package from Taiwan was reported at 11:18 a.m. on Friday at a detached house in Jusan-dong, Dong-gu, Daejeon. Investigators collected the package and sent it to the National Forensic Service.

The parcel was confirmed to have been delivered from Taipei, Taiwan, but the sender's identity is yet to be confirmed.

Police checked surrounding addresses for similar international mail and found another parcel sent from Uzbekistan, for which they requested an inspection.

The Dong-gu Office in Daejeon sent an emergency alert text message to residents there, urging them not to open any international packages with unclear sources, and to report the receipt of any such packages immediately.

Suspected parcels were also found at several post offices in Seoul, including Seocho and Songpa. Police, fire authorities, and the military search team were dispatched, Friday afternoon.

Some 1,700 people at the Seoul Central Post Office in Myeong-dong evacuated after a police report was filed at around 4:06 p.m., and the contents of the package are being checked by the authorities.

Most of the parcels found so far have been shipped from Taiwan and are wrapped in yellow or black bags. Some are from Uzbekistan, Ukraine, and Malaysia.

The phrase "CHUNGHWA POST" was found on most of the suspicious packages, reportedly.

Earlier, a package suspected to contain toxic materials, which also originated from Taiwan, was delivered to a welfare facility for the disabled in Dong-gu, Ulsan, Thursday. Three people reported suffering from dizziness following exposure.

The package was delivered to the facility around noon that day. Upon opening it, three employees experienced difficulty breathing and symptoms of paralysis, according to a statement from the Ulsan Fire Department on the same day.

Three employees -- a man in his 50s and women in their 30s and 40s -- were transported to a nearby hospital by police. According to reports, they were receiving treatment, but their lives were not in danger.

The package was contained in a yellow bag, and was discovered to contain a colorless, odorless powder.

Due to the potential that the substance could be harmful, police blocked the entrance to the welfare facility and relocated 50 students to alternate buildings. Fire authorities are working to identify the exact nature of the powder found in the package.

In another case, a man who received a similar package in Jeju City on July 11 reported it to police on Thursday. The man was about to throw the package away, but decided to report it to police as the package he received had several similarities to the package found in Ulsan.

The package found on Jeju Island was also shipped from Taiwan and was contained in yellow wrapping paper.

An official from the fire authorities demanded caution saying, "If you receive mail or packages that you have not ordered from abroad, do not open it and report it to 112 or 119 immediately."

The Postal Service temporarily suspended suspicious international packages, as concerns were growing over some random parcels that might contain an unspecified hazardous material.

The move came after a flurry of reports came in nationwide of receiving random parcels mostly from Taiwan, in recent days.

On Thursday, such a parcel caused three people who unpacked it to suffer dizziness and difficulty breathing at a welfare center for the disabled in the southeastern port city of Ulsan.

The three people have been admitted to hospital and are now said to be in stable condition.

While medical tests did not immediately point out what caused the symptoms, police did not rule out a toxic chemical agent might have caused the infections.

The parcel has been sent to the Agency for Defense Development for further analysis.

The police said the name of the recipient and the phone number written on the parcel were invalid.

Authorities also found a similar package around 6 p.m. Friday while sorting out parcels at a post office in the same city. Fire officials were dispatched to the scene and assessing the damage.

Similar reports also came from Seoul, Yongin, a suburb of Seoul, Jeju Island, Haman in South Gyeongsang Province and Daejeon.

In Seoul, some 1,700 people were temporarily evacuated from a building in the popular shopping district of Myeongdong on Friday, after a suspicious yellow parcel was spotted in the post office located on the first floor of the 21-story building.

No casualties have been reported.

Minister of Science and ICT Lee Jong-ho canceled his scheduled attendance at a talk with Andrew Ng, a prominent artificial intelligence researcher and a computer science professor at Stanford University, on Friday night to monitor the situation.

A person on Jeju reported to the authorities about receiving a random parcel on July 11, which was sent from Taiwan and contained two plastic bottles. The person threw them away, but later reported them to the police on Thursday after hearing about the suspicious package in Ulsan.

A random parcel spotted in Haman was sent from Malaysia, police said. The recipient had kept the parcel for about two months and reported it to the police, also after learning about the Ulsan parcel.

Authorities asked for vigilance if a random package arrives, and called on recipients not to open it and report it to authorities instead.

They said the color of such packages could be yellow or black, and could have "CHUNGHWA POST" written on them. The sender could be P.O. Box 100561-003777, Taipei Taiwan.