Police said Monday that they have not ruled out drug use allegations concerning G-Dragon, despite lifting travel restrictions on the K-pop icon after a detailed narcotics analysis of his biological samples came back negative.

An official of the National Police Agency said in a regular press briefing that the officials are "open to possibilities until the investigation reaches its conclusion" on the G-Dragon probe.

"If the circumstances clearly point to drug use, it wouldn't be right to not press charges just because the tests were negative...Past legal cases (on drug uses) show that a guilty verdict has been reached despite negative test results," the official said.

G-Dragon has been grounded by travel restrictions imposed by the Incheon Metropolitan Police Agency investigating his suspected use of narcotic substances last month, and expired Saturday.

South Korean law stipulates that the Justice Minister has the authority to grant a travel ban for as long as a month to individuals under investigation, which can be extended upon request from the police with probable cause.

The Incheon police department has been conducting a probe on G-Dragon's alleged drug use based on a tip-off it got while investigating drug use allegations of another celebrity of international fame, actor Lee Sun-kyun. Lee is best known for appearing in the movie "Parasite."

Lee also tested negative for narcotic substances, but police requested an extension for his travel ban, based on text messages and other evidence that indicated drug use.