Former U.N. Secretary-General Ban Ki-moon on Thursday reiterated his presidential ambitions, calling for joint efforts to bring together a nation suffering from a slew of economic, security and political challenges.

Upon arriving at Incheon International Airport, west of Seoul, Ban, a former foreign minister, fell short of officially declaring his presidential bid, but he stressed that he would “be with citizens for a change of politics, not for a change of government.”

Korea’s Yonhap news agency quoted him as saying: “I have already said that I am ready to give my all (for the country) and my determination remains unchanged,” he told a cheering crowd of citizens at the airport.

Ban, whose second five-year term as the U.N. helmsman ended at the end of last year, has been long bandied about as a formidable presidential candidate, with various recent opinion polls putting him in second place slightly behind Rep. Moon Jae-in.

Korea’s first female president, Park Geun-hye, was impeached by parliament in December over an influence-peddling scandal. Ban was accompanied by his wife Yoo Soon-taek as well as an aide and security staff. According to Yonhap News Agency, he said his heart “felt like bursting” with excitement at the thought of returning to South Korea.

Meanwhile, Ban said he was “perplexed and embarrassed” over bribery accusations brought by U.S. prosecutors this week against his brother and nephew.

Ban’s younger brother Ban Ki-sang and his nephew Joo Hyun Bahn were accused in a Manhattan federal court on Tuesday of a scheme to bribe a Middle Eastern official for an attempted $800 million sale of a building complex in Vietnam.

“I am perplexed and embarrassed that close members of my family have become involved in something like this. I feel it is regrettable the situation has troubled many,” Ban told Korean reporters at John F. Kennedy International Airport on Wednesday ahead of his departure for South Korea.

“I had absolutely no knowledge. My nephew is grown and I barely had any involvement in his life or how he does business,” he said in remarks broadcast on South Korean TV.

Controversy around the building deal linked to Ban’s relatives had been reported previously in South Korean media and Ban made similar remarks regarding the case in 2015.

In September, a Seoul district court ordered Ban’s nephew to pay civil damages of about $590,000 to builder Keangnam Enterprises. The court said the nephew had fraudulently led Keangnam to believe that the Qatar Investment Authority was close to buying the Vietnam skyscraper.

In emails cited in the U.S. indictment, Ban’s nephew is shown to be using the family name in an attempt to secure the deal, and expressed concern that negative media coverage if it fell through would be bad for the family given its prominence.

His nephew Bahn, a 38-year-old South Korean national living in New Jersey, pleaded not guilty during a Tuesday court hearing. His father was not arrested and could not be reached immediately for comment.

Source: Yonhap News Agency and Reuters