BOGOTA (Reuters) - Colombian President-elect Ivan Duque on Monday admitted he faces great challenges when he takes office next month and said while he is not a miracle worker, he will do all he can to push the nation forward and reduce the gulf between rich and poor.

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Duque, a right-winger who will replace President Juan Manuel Santos on Aug. 7, received accreditation from Colombia’s electoral council confirming him as the legitimate winner of last month’s election.

Standing alongside his vice president, Marta Lucia Ramirez, Duque said he would strengthen security in the nation, protect community leaders threatened by crime gangs, reduce cultivation of illicit crops and bolster the economy.

“We will not be inferior to the challenge that history gives us, we will not be inferior to the motivation that we have to work intensely,” Duque said during the ceremony as family and colleagues cheered.

“Here there will be no miracles, there will be hard work and if we unite Colombia around these common goals, we will turn them into the greatest opportunity in our history.”

Duque, 41, a business-friendly protégé of hard-line former President Alvaro Uribe, said he would present a series of anti-corruption policy measures to congress on the day he is sworn in to office.

Duque has promised to unite the Andean nation after years of antagonism over a peace agreement with the Revolutionary Armed forces of Colombia (FARC) that ended the group’s part in five decades of conflict but angered many voters who want to see former rebel commanders jailed for crimes.

Duque has promised to impose tougher punishments on rebels for war crimes.

He faces significant difficulties when he takes office. The economy remains weak; drug trafficking gangs have moved into areas once controlled by the FARC; and more than 800,000 Venezuelan migrants have crossed into Colombia, looking for food and work.

He has promised to bolster the $324 billion economy, keep investors happy by cutting business taxes, support the oil and coal sectors - top exports - and help manufacturing.

But he needs to show he is tackling inequality, corruption and inadequate social services if he wants to avoid creating opportunities for the left in future, possibly as soon as 2022, analysts have said.

A one-term senator, Duque worked at the Inter-American Development Bank in Washington, served as a consultant at the Andean Development Corporation (CAF) and as adviser to Santos when he was finance minister in former President Andres Pastrana’s government.