RICHMOND, Va. — Nine days after announcing that there would be 24 franchises competing for the 2010 United Bowl Championship, the Indoor Football League announced the addition of two more teams for the 2010 season on Thursday.

The league confirmed that the Arkansas Twisters and Tri-Cities Fever — both formerly of the now-defunct af2 — were voted into the league by its owners during a Thursday conference call.

“It is an exciting period of time in the young history of the IFL,” stated IFL commissioner Tommy Benizio. “This was a rare opportunity to add two exceptional teams to the league and we are thrilled about what we feel they can bring to the IFL.”

Arkansas, which plays its home games in North Little Rock, is entering its 11th season of indoor football and looking to build on its past success. The Twisters have made the playoffs six out 10 years, appearing in the af2 championship game in 2003 and 2006.

The Fever joins the IFL after achieving success in both the National Indoor Football League (NIFL) and the af2. In their inaugural season, the Fever won the 2005 Indoor Bowl Championship while participating in the NIFL.

The addition of Tri-Cities renews an intense NIFL rivalry with the Billings Outlaws.

The Outlaws’ lone loss of their 2006 championship season came at the hands of the Fever when a last-second field goal by kicker Pete Garces was ruled no good. Billings avenged the Week 2 loss in Kennewick, Wash., later in the season, knocking Tri-Cities off in the first round of the NIFL playoffs.