Nigeria’s President Muhammadu Buhari plagiarized quotes from President Barack Obama in a speech promising change in his country, according to a statement by the presidential office.

Muhammadu Buhari has blamed an “overzealous” staff member for plagiarizing parts of the speech.

He made the address on September 8 to launch a campaign entitled “Change begins with me,” part of his credo to end corruption in Africa’s biggest economy, which is gripped by mismanagement and poverty despite sitting on vast energy reserves.

Several passages of his speech overlapped with President Obama’s address after winning election in 2008.

Muhamamadu Buhari’s office admitted the sentences were “too close to be passed as coincidence”.

The Nigerian president and Barack Obama are due to meet at the UN General Assembly next week.

“There was a mistake by an overzealous staff and we regret that this has happened,” Muhammadu Buhari’s spokesman Garba Shehu wrote on Twitter, saying those responsible would be punished.

“President Buhari urges Nigerians to look beyond this incident and focus on the message of change which the country needs in order to restore our cherished value systems.”

Muhammadu Buhari’s speech read: “We must resist the temptation to fall back on the same partisanship, pettiness and immaturity that have poisoned our country for so long.”

Barack Obama’s speech read: “Let us resist the temptation to fall back on the same partisanship and pettiness and immaturity that has poisoned our politics for so long.”

Nigeria, which ranks 136 out of 168 countries in Transparency International’s Corruption Perception Index for 2015, has struggled for years to fight corruption among its political elite.

But since Muhammadu Buhari was elected to power in 2014 on a campaign that vowed to root out corruption, anti-fraud agencies have arrested several senior politicians accused of embezzlement.

Earlier this year Donald Trump’s wife, Melania, was accused of plagiarizing portions of Michelle Obama’s 2008 Democratic National Convention speech.