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Re-elected Finnish President Sauli Niinisto (L) and his wife Jenni Haukio greet the public from the balcony of the Presidential Palace during presidential inauguration on February 1, 2018 in Helsinki, Finland. (AFP PHOTO/Lehtikuva/Markku Ulander/ Finland OUT)

HELSINKI, Feb. 3 (Xinhua) -- Finnish President Sauli Niinisto and his spouse Jenni Haukio had a son on Friday evening, one day after he was inaugurated as the president for a second six-year term.

Niinisto announced the birth both on his personal Facebook account and in a press release of the presidential office.

The president thanked for the congratulations the couple has received. The website of the presidential office collapsed for some minutes after the announcement.

Niinisto, now 69, and Jenni Haukio, now 40, got married in 2009. When married, Mrs Haukio chose to keep her surname.

Finnish media started speculation about the child's name. As the parents have different surnames, they have to decide whether the son will be a Niinisto or a Haukio.

The son was born at the Women's Clinic of the Helsinki University Hospital, located in Meilahti, a few kilometers from the official residence of the president. The hospital is currently the only hospital offering birth services in Helsinki.

Niinisto's previous wife Marja-Leena died in an auto crash in 1995. Niinisto has two adult sons from his previous marriage.

The baby is Haukio's first child.

Before the marriage, Haukio worked as the information chief of the Finnish conservative party. Their dating had been known by a very small circle only prior to the wedding.

This is the first time a Finnish president gets offspring while in office.