Updated

The founder and leader of Poland's junior opposition party Modern has lost his top position as the party seeks to boost its image and standing.

In a close vote Saturday, the party's national convention chose prominent member Katarzyna Lubnauer to replace economist Ryszard Petru, who founded the party before the 2015 election in which it won 28 seats in the 460-member parliament.

But it then failed to grow under Petru's leadership and got involved in a bitter rivalry with the main opposition party, Civic Platform. Petru was also absent at some crucial political moments.

On Saturday, Petru was backed by 140 votes, and Lubnauer by 149 votes, a result that exposed deep divisions in the party.

Lubnauer vowed to unite it and raise its liberal, pro-business profile.