Operation of the first regular ferry service between North Korea and Russia has been halted after increased U.N. sanctions in response to Pyongyang's ballistic missile tests kept passenger and freight demand low, its operator said Saturday.

The Russian operator, InvestStroiTrest, told Kyodo News that authorities denied the boat, named the Mangyongbong, entry to a port in Vladivostok, Russia, in August as the shipping firm could not pay the 1 million ruble ($17,000) docking fee.

The shipping firm said the ferry service, which started in mid-May, is a business and does not serve any political purpose, though Japan expressed concern about the possibility of revenue earned from the ferry operation being funneled to Pyongyang's nuclear and missile development program.

In early August, the U.N. Security Council banned North Korea from exporting coal, iron, lead and seafood to curb the country's export revenue after two intercontinental ballistic missile tests were undertaken in July in defiance of past resolutions banning nuclear and missile activities.

The resolution also forbids U.N. member countries from increasing the number of laborers accepted from North Korea.

About 40 North Korean crew members on the ship were giving some 40 percent of their salaries to the government.

The shipping company said the weekly ferry service between the Rason Special Economic Zone on the northeastern tip of North Korea and Vladivostok was unable to generate the level of income initially expected after the imposition of U.N. sanctions.

It expected to carry more than 100 passengers on each trip, but there were times when only a small number of people made the journey, it said.