After Tuesday night's hotly contested Boston City Council election, at least one at-large city council seat remains contested.

At-Large Candidate Alejandra St. Guillen told WGBH News Wednesday that she is moving forward with petitioning for a recount after the unofficial vote tally showed her just 10 votes behind opponent Julia Mejia for the Council's fourth at-large member seat.

St. Guillen indicated to supporters that she was conceding the race late Tuesday, when Mejia’s lead appeared to be larger. But as the final 10-vote split became apparent even later in the evening, St. Guillen said she intends to petition for a recount.

In Boston, any candidate for city office has to petition for a recount in each individual city ward they want recounted. The candidate must submit a petition with at least 50 resident signatures per ward to trigger a recount there. St. Guillen said she will likely pursue a recount in each of the city's 22 wards, and will begin collecting signatures on Thursday.

The deadline for submitting recount petitions is Friday, Nov. 15.

There are still nine days for the Boston Election Department to count any overseas or military absentee ballots.

Reached by phone Wednesday, Mejia said she was proud of her campaign and expressed confidence in the process of a recount, should one take place.

“This is such a great moment for the community to recognize that even with 10 votes, they can make a difference,” Mejia said. She added, “I think it’s a teachable moment and it’s part of democracy, and let’s support the process.”