SAN LEANDRO -- Mayor Tony Santos said Thursday that he is not set to concede the mayor's seat for the next four years, despite unofficial results that show him losing his re-election bid by less than 200 votes.

"I'm far from conceding the race," he said. "I still have a lot of questions about the election."

The Alameda County's Registrar of Voters Office released its unofficial final ranked-choice voting results in the mayor's race Wednesday night, showing former school board trustee Stephen Cassidy edging out Santos.

Cassidy had 50.4 percent of the vote, or 10,119 votes, while Santos had 49.6 percent, or 9,947 votes, a difference of 172 votes.

Santos said he would look into rules governing elections in the city's charter.

He said one of his concerns was that neither he nor Cassidy received the majority of votes cast in the mayor's race, since ballots that did not contain a first-, second- or third-place vote for either candidate would not have made it to the final round of the ranked-choice voting tabulation. They are known as "exhausted ballots," and there were 2,099 such ballots in the San Leandro mayor's race.

Santos, who was a strong supporter of the city switching to ranked-choice voting, said he was not sure how far he wants to push questioning the election but would not concede yet. He added that he may ask for a total recount and also try to seek a runoff election between himself and Cassidy.

Dave Macdonald, the county's registrar of voters, said someone may ask for a recount but must pay for such an endeavor. He added that recounts do not really differ from the way his office does the original count, but anyone still may ask for a second count.

Macdonald said he did not have a good idea of the cost of a recount.

Cassidy, on the other hand, said that he was glad that the election was finally over and was gratified that voters turned out for him.

He said he had no issues with the ranked-choice election process.

"Everyone knew the rules of this election and for someone now, who did not win, to claim the rules are unfair shows disrespect for the democratic process and the voters," Cassidy said.

This was the first time ranked-choice voting has been used in San Leandro elections. Ranked-choice voting -- also known as instant-runoff voting -- allowed voters to rank their first-, second- and third-choice candidates for a single office. If no candidate receives more than 50 percent of the vote when ballots are tallied, the ranked-choice voting system kicks in. The system starts eliminating candidates from the bottom up. When a voter's first choice is eliminated, their second choice is then counted.

This process of elimination occurs until a candidate has 50 percent of the vote.

The system eliminates the need for a primary.

However, all votes must be verified and counted before the process can produce an accurate result -- which was why unofficial results of the mayor's race were not known until Wednesday.

Those results are not final until the registrar certifies them later this month. State law requires that counties certify results by Nov. 30.