JUNEAU, Alaska — Just one debate so far will feature the four main candidates for the U.S. Senate seat, with participation in three others unclear.

Republican Sen. Lisa Murkowski, Democrat Ray Metcalfe, Libertarian Joe Miller and independent Margaret Stock have said they will take part in the public broadcasting debate Nov. 3, said Lori Townsend, news director for the Alaska Public Radio Network and moderator for that debate.

Murkowski also has committed to a fisheries debate Oct. 12 in Kodiak; an Alaska Federation of Natives’ candidate forum in Fairbanks Oct. 21; and a debate on the Arctic in Barrow on Oct. 26. The Kodiak debate will be carried by the local public radio station, but it wasn’t immediately clear if the Fairbanks or Barrow events would be on radio or television.

Murkowski spokesman Robert Dillon said by email that it was important to Murkowski to appear at events reflecting Alaska’s geographic, economic and demographic diversity.

Miller called on Murkowski to participate in televised debates. He said the debate schedule agreed to by Murkowski isn’t fair to voters trying to make an informed decision, and his campaign suggested some of the venues might be friendly to Murkowski, such as the Alaska Native forum. However, spokesman Randy DeSoto said Tuesday that they hadn’t decided which of the events Miller would attend beyond the public radio debate.

Dillon said there’s nothing preventing Miller from going to any of the debates. He also said there is nothing stopping television stations from covering the debates or scheduling their own, as they have done in the past. But he said these are the four events Murkowski plans to attend.

At least two of the events — those focused on the Arctic and fisheries — extended invitations to Murkowski, Miller, Metcalfe and Stock as well as two lesser-known candidates running as independents, according to organizers. Stock spokeswoman Amy Jackman said Stock plans to take part in both.

A spokesman for the Alaska Federation of Natives hasn’t responded to requests from The Associated Press about who has been invited and who has committed to the federation debate besides Murkowski. In interviews, Metcalfe said he plans to participate, and Jackman said Stock would as well. DeSoto said he was trying to connect with the forum’s point of contact.