A man has been arrested on suspicion of driving a snowmobile into two dog teams competing in the Iditarod Trail Sled Dog Race in Alaska early Saturday morning, killing one dog and injuring at least three others.

Mushers Aliy Zirkle and Jeff King were hit outside the village of Nulato, a community of 236 on the Yukon River a little more than halfway into the 1,600-kilometre race to Nome.

Alaskan State Troopers say 26-year-old Arnold Demoski is being held on two counts of assault, reckless endangerment, reckless driving and six counts of criminal mischief.

Demoski told local media that he had not intentionally driven into the dog teams, but had blacked out while returning from drinking in another village,

Aliy Zirkle at the start of the 2016 Iditarod. (Aliy Zirkle/Facebook)

Race marshal Mark Nordman said Saturday that Zirkle, 46, who finished second three times from 2012-2014, was mushing from Koyukuk to Nulato, a run of less than 32 kilometres on the Yukon River, when she was hit.

The snowmobile hit the side of Zirkle's sled about 8 km out of Koyukuk, turned around multiple times and came

back at her before driving off, Alaska State Troopers spokeswoman Megan Peters said by email.

The snowmobile reappeared about 19 kilometres out of Nulato. He revved up and was pointed at Zirkle before leaving,

Peters said.

One dog on her team was bruised. Officials described the injury as non-life-threatening.

1 dog dead, others injured

King, a four-time Iditarod champion, was behind Zirkle and fared worse.

When King reached the vicinity, he was struck from behind by the snowmobile and at least three of his dogs were hit. Nash, a 3-year-old male, was killed. Crosby, another 3-year-old male, and Banjo, a 2-year-old male, received injuries and are expected to survive.

Race officials said King received medical attention in Nulato, but troopers quoted King as saying he was not injured.

Troopers also said five of King's dogs were injured.

Zirkle left Nulato with 14 dogs at 6:16 a.m., after dropping one dog in the village. She was in third place.

The race leader is former champion Mitch Seavey, who reached Kaltag at 7:41 a.m.

Brent Sass was running second. He left Nulato at 3:43 a.m.

Reigning champ Dallas Seavey, the son of Mitch Seavey, was in fourth place. He left Nulato at 7:14 a.m.