Image copyright AFP/Getty Image caption Kim Jong-un and top military officials celebrated Friday's missile launch

North Korea has warned that more sanctions and pressure will only make it accelerate its nuclear programme.

In a strongly worded statement, Pyongyang called a new set of UN sanctions "the most vicious, unethical and inhumane act of hostility".

Meanwhile, the presidents of the US and China committed to "maximising pressure" on the North through vigorous enforcement of UN resolutions.

Earlier, the US and South Korea carried out joint military exercises.

North Korea fired its latest missile over Japan on Friday. It travelled 3,700km (2,299 miles), putting the US Pacific territory of Guam, which North Korea says it has a plan to target, within reach.

The launch followed a fresh round of UN sanctions and was unanimously condemned bythe UN Security Council as "highly provocative".

What has North Korea said?

The foreign ministry statement, carried by the country's official news agency KCNA, said: "The increased moves of the US and its vassal forces to impose sanctions and pressure on the DPRK [Democratic People's Republic of Korea] will only increase our pace towards the ultimate completion of the state nuclear force."

It also said that the goal of the new UN sanctions, approved on 11 September, was to "physically exterminate" the country's people, system and government.

The sanctions are an attempt to starve North Korea of fuel and income for its weapons programmes, and restrict oil imports and ban textile exports.

The fresh measures followed the sixth and most powerful nuclear test conducted by Pyongyang earlier this month.

But some critics have raised