BEIJING (Reuters) - China on Tuesday banned imports of gold and rare earths from North Korea as well as exports to the country of jet fuel and other oil products used to make rocket fuel, a move in line with new United Nations sanctions on Pyongyang.

North Korean leader Kim Jong Un salutes as he arrives to inspect a military drill at an unknown location, in this undated photo released by North Korea's Korean Central News Agency (KCNA) on March 25, 2016. REUTERS/KCNA

The Security Council unanimously passed a resolution in early March expanding U.N. sanctions aimed at starving North Korea of funds for its nuclear and ballistic missile programs after Pyongyang conducted a fourth nuclear test in January and launched a long-range rocket in February.

The mining sector is a key part of North Korea’s economy, which is already largely cut off from the rest of the world. Experts believe revenue from the sector helps underwrite North Korea’s military expenditures.

The ministry said it would also ban coal shipments from North Korea, although it made exemptions consistent with sanctions, including uses intended for “the people’s well-being” and not connected to nuclear or missile programs.

North Korea delivered around 20 million tonnes of coal to China last year, up 27 percent on the year, overtaking Russia and Mongolia to become China’s third biggest supplier, behind Australia and Indonesia.

An exception was made for coal originating in third countries and supplied via North Korea’s port of Rason. Landlocked Mongolia, looking for alternative supply routes for its commodities, has already signed an agreement with the port that gave its exporters preferential treatment.

Export bans on jet and rocket fuel included exemptions for “basic humanitarian needs” in conjunction with inspections, and for civilian passenger jets flying outside of North Korea.

Other restricted minerals include vanadium and titanium, both used in steel alloys.

Independent experts have frequently questioned China’s resolve to enforce sanctions against North Korea, whose economy is heavily dependent on its neighbor. China has said it will enforce the measures “conscientiously”.

U.S. State Department officials have expressed optimism the sanctions will be more effective than earlier attempts to curtail North Korea’s nuclear program, pointing to China’s apparent willingness to support them.

China disapproves of North Korea’s nuclear program, although, as its sole major ally, it has supplied large quantities of aid off the books for decades.