* Catholic church has been mediating last-ditch talks
* “A miracle is possible,” opposition says
* Deal says Kabila cannot have a third term in office
* Repression of anti-Kabila protests killed 40 this week (Adds opposition insists on Kabila leaving by November 2017, paragraph 9)
By Aaron Ross and Tim Cocks
KINSHASA, Dec 23 (Reuters) - Congolese politicians have agreed in principle to a deal under which President Joseph Kabila leaves office by the end of 2017, opposition leaders said on Friday, an unexpected breakthrough after dozens were killed in anti-government protests this week.
If the deal does succeed, it would be a major achievement for the Catholic church, which has been mediating talks in an attempt to prevent Democratic Republic of Congo sliding back into years of anarchy and civil war.
Pope Francis has heaped pressured on Kabila and the opposition to find a peaceful solution to the crisis in Congo.
“At first glance, a miracle is possible and the bishops have won their bet,” Albert Moleka, former chief of staff to the leader of the main opposition bloc Etienne Tshisekedi, said.
A government spokesman said the proposal would be presented to the full delegation at the talks on Friday afternoon, but he declined to comment on the specifics of the deal.
In return for Kabila staying on for another year, the constitution will not be changed to let him stand for a third term, a prime minister will be named from the main opposition bloc and Tshisekedi will oversee the deal’s implementation, opposition leaders Martin Fayulu and Jose Endundo told Reuters.
“Kabila stays for one year,” Fayulu said. “He will not try to stand for a new term.”
However, Kabila himself has so far said nothing and the parties have yet to sign the deal, which requires final approval by all delegates at the talks.
The negotiations could still be tough, with the opposition insisting on Friday that Kabila step down in time for elections to take place no later than November 2017.
Church leaders have presented these talks as a last ditch effort to prevent violence spinning out of control after a bloody week that saw protesters killed and deadly clashes between various ethnic militia across the country.
The head of the U.N. human rights agency said on Friday that Congolese security forces had killed at least 40 people and arrested 460 in protests this week.
The violence has raised fears Congo is heading toward another major armed conflict, a risk that has prompted several donor nations to condemn Kabila for failing to stand down.
Millions were killed in wars between 1996 and 2003.
“Most of ... (Kabila’s coalition) would welcome this (deal) because they’re under so much pressure,” said Pascal Kambale, a Congolese human rights lawyer working for the Open Society Foundations.
But Jean Marc Kabund, the secretary general of Congo’s largest opposition party, the UDPS, warned that the deal was not yet a sure thing.
“Today is the last day (of negotiations),” he told Reuters. “It’s make it or break it.”
A presidential election scheduled for last month had been postponed until at least April 2018 because of what the government said were delays registering voters. This deal would mean it must happen by the end of next year.
Kabila has declined to commit publicly to not changing the constitution to extend his term, leading many to conclude that this is what he secretly wants to do.
His allies have argued that he is committed to respecting the constitution but that promising to step down would make him a lame duck and possibly spark a power struggle that could put his life in danger.
His father, President Laurent Kabila, was assassinated by a bodyguard in 2001 and Congo has never had a peaceful transition of power.
It was not immediately clear how the wider population would react to an agreement. On Twitter, a leader of the youth activist group Filimbi, Floribert Anzuluni, said it constituted “high treason by everyone”.
However, many in the capital Kinshasa, who spoke to Reuters after the protests subsided, said they were tired of the violence and hoped for a negotiated settlement. (Editing by Tim Cocks and Louise Ireland/Richard Balmforth)