LONDON (Reuters) - A humanitarian crisis in central Democratic Republic of Congo is easing, Prime Minister Bruno Tshibala told Reuters on Thursday, after confirming an election to replace President Joseph Kabila remains on course for late December.

The Kasai region is Congo’s biggest security challenge and has been the scene of a growing humanitarian disaster. But the situation there “seems to be improving”, Tshibala said in an interview conducted in London on Thursday.

U.N. Secretary General Antonio Guterres said in a report on Wednesday that 13.1 million Congolese need humanitarian assistance, twice as many as last year, and that 7.7 million face severe food insecurity, up 30 percent from a year ago.

“The situation is under control,” said Tshibala. Asked about reports of aid workers killed in the country, he said: “We ensure security through our armed forces and police. Humanitarian workers are welcome and are protected.”

Over the last two years, DRC security forces have killed dozens of civilians protesting about election delays. At least two were killed in a crackdown late last month in Kinshasa.

Worsening militia violence has meanwhile raised fears Congo is sliding back towards the civil wars of the turn of the century that killed millions. But Tshibala shrugged off militia groups active throughout the country as lacking political aims.

Much of the unrest stems from Kabila’s extended stay in office. His presidential mandate expired at the end of 2016 but has so far refused to step down.

Tshibala said an election -- repeatedly stalled -- to replace Kabila is on course for December.

“I committed in front of our country’s representatives in May last year to my mission, which was to bring the Congolese people to elections this year, and I confirm that in December this year the Congolese people will be brought to the ballot boxes,” Tshibala said.

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“There were setbacks which caused this delay. But this time our course is set for elections and they will take place on Dec. 23.”

A former leading member of Congo’s main opposition coalition, Tshibala was appointed by Kabila just under a year ago to head a transitional ‘unity’ government tasked with organizing the election.

Asked about technical problems experienced by voting machines during recent testing in the capital Kinshasa, he said: “Machines are a great revolution” that would help the election to run smoothly and in record time.

“We have taken all the precautions with the electoral commission for it to go well. It’s true that it’s a vast country ... but that’s exactly why the voting machines will help improve the process.”

Opponents of Kabila, who has ruled Congo since his father Laurent’s assassination in 2001, suspect he intends to repeatedly delay elections until he can organize a referendum to let himself stand for a third term, as his counterparts in neighboring Congo Republic and Rwanda have done.

Kabila denies those charges, saying the election delays are due to challenges registering millions of voters and budgetary constraints.

NO CHANGE TO NEW MINING CODE

Congo, which is nearly the same size as western Europe, has plentiful resources and is implementing new mining laws to increase the revenues it gets from miners active in the country.

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It is Africa’s largest copper producer and the source of more than half the world’s cobalt, a vital ingredient in mobile phone and electric vehicle batteries. Its output of cobalt jumped 15.5 percent last year.

The new laws are fiercely opposed by international mining conglomerates, which are concerned Congo will raise taxes and royalties and remove a stability clause in the current law protecting miners from fiscal changes for 10 years.

Kabila held a nearly six hour long meeting with miners on Wednesday to discuss the laws.

But on Thursday Tshibala told Reuters the new code will be signed into law without changes.

He was unable to specify how much extra revenue the changes would generate and said the economic situation remains difficult. The central bank currently predicts inflation will be 38 percent by the end of 2018.

“We are making an internal effort to improve tax collection and government receipts,” said Tshibala.

“If we find ourselves in a difficult situation we won’t hesitate to speak to the international financial institutions to provide a supplement in order to improve our functioning as a state.”