North Korea fired two unidentified projectiles from South Hwanghae province into the sea to the east, Yonhap news agency said today citing South Korea's Joint Chiefs of Staff.

The move comes as North Korea said that the joint military drill being conducted by the United States and South Korea violates agreements North Korea made with them, state media KCNA said.

North Korea remains "unchanged in our stand to resolve the issues through dialogue," the statement said, but "we will be compelled to seek a new road as we have already indicated," if the two countries continue with "hostile military moves".

Meanwhile, North Korea has generated an estimated $2bn for its weapons of mass destruction programmes using "widespread and increasingly sophisticated" cyber attacks to steal from banks and crypto-currency exchanges, according to a confidential UN report.

The North Korean mission to the United Nations did not respond to a request for comment on the report, which was submitted to the Security Council committee last week.

The experts said North Korea "used cyberspace to launch increasingly sophisticated attacks to steal funds from financial institutions and crypto-currency exchanges to generate income.

"They also used cyberspace to launder the stolen money," the report said.

The experts in the report said they are investigating "at least 35 reported instances of DPRK (Democratic People's Republic of Korea) actors attacking financial institutions, crypto-currency exchanges and mining activity designed to earn foreign currency" in some 17 countries.

The UN experts said North Korea's attacks against crypto-currency exchanges allowed it "to generate income in ways that are harder to trace and subject to less government oversight and regulation than the traditional banking sector".

The Security Council has unanimously imposed sanctions on North Korea since 2006 in a bid to choke funding for Pyongyang's nuclear and ballistic missile programmes.

The Council has banned exports including coal, iron, lead, textiles and seafood, and capped imports of crude oil and refined petroleum products.

US President Donald Trump has met North Korea leader Kim Jong-un three times, most recently in June when he became the first sitting US president to set foot in North Korea at the Demilitarized Zone (DMZ) between the two Koreas.

They agreed to resume stalled talks aimed at getting Pyongyang to give up its nuclear weapons programme.

The talks have yet to resume and in July and early August already, North Korea carried out three short-range missiles tests in eight days.