SINGAPORE/HANOI--A Vietnamese tanker was bound for North Korea carrying 2,000 tons of gasoline, Refinitiv shipping data showed, just as North Korean leader Kim Jong Un and U.S. President Donald Trump prepared for key talks on security and cooperation in the Vietnamese capital Hanoi.

The vessel, the Viet Tin 01, arrived just outside the harbor of Nampo on North Korea's western coast on Feb. 25 carrying 2,000 tons of gasoline, according to the data compiled by Refinitiv. The data tracks ships' movements as well as providing details of their cargoes and official destinations as registered by shippers.

It wasn't immediately clear whether the tanker unloaded cargo at Nampo. Under sanctions imposed by the United Nations, North Korea is heavily restricted in its imports of crude oil and refined petroleum products.

Trump and Kim began a second day of talks on Thursday, with both sides expressing hope for progress on improving relations and the key issue of denuclearization in the pair's second summit meeting.

The 5,000 deadweight ton tanker--small by industry standards--was scheduled to deliver the fuel to Daesan in South Korea, according to its official destination registered in the shipping data. The vessel still showed Daesan as its destination as of Feb. 28, according to the data.

The Viet Tin 01's previous stops were Taiwan, Singapore and Bangladesh. It was not immediately clear where the ship loaded the gasoline.

An official for the ship's registered owner, Ho Chi Minh City-based Viet Trust Shipping Corp., said she was not aware of the ship's whereabouts. She said the company owned two ships, the Viet Tin 01, and the Viet Tin Lucky, which is currently off the west coast of Thailand.

The Vietnamese foreign ministry did not respond to a request for comment.

News outlet NK Pro, which monitors North Korea developments, said in a report on Thursday "the transfer would likely push against U.N. resolutions" under which its fuel imports are restricted.