SEOUL: A hotel located along a sloped alley, where the deadly crowd crush happened, illegally extended its terrace, a document showed Tuesday, suggesting the construction made the narrow path even narrower.

At least 156 people, mostly in their 20s, were killed and 30 others were seriously injured in South Korea's deadliest crowd surge that happened in the famous nightlife district of Itaewon on Saturday night, after tens of thousands of people visited the area for Halloween.

The Hamilton Hotel located right next to the downhill alley illegally extended a 17.2-square-meter terrace on its northern side of the main building, reported Yonhap citing the hotel's building ledger.

The terrace is located on the famous street -- filled with bars and restaurants -- that is connected to the 50-meter-long downhill alley with a width of about 5 meters at the top and 3.2 meters at the bottom.

The ward office of Yongsan, which includes Itaewon, already notified Hamilton Hotel of the violation and levied relevant fines last year, officials said.

Earlier in the day, National Police Agency Commissioner General Yoon Hee-keun told reporters that the police will look into whether Hamilton Hotel violated relevant laws.

-- BERNAMA