The Big 12 announced Friday night it is adding Arizona, Arizona State and Utah as members next year, completing its raid of the Pac-12.

The latest blow to the Pac-12, came just hours after the Big Ten welcomed Oregon and Washington to grow its new West Coast wing next year. A little more than a year ago, Southern California and UCLA announced they were joining the Big Ten in 2024. With the Ducks and Huskies, too, the Big Ten will be an 18-team conference.

The Big 12 has been targeting the Pac-12’s so-called Four Corner state schools for months, with Colorado making the jump last week.

The additions of the Arizona schools and Utah give the Big 12 16 schools, stretching from Florida to Arizona.

Dealing a combination of crushing blows to the Pac-12, the Big Ten announced Friday it will accept Oregon and Washington as new members next August, and the Big 12 was poised to complete its raid of the beleaguered conference on the West Coast.

The Big Ten earlier in the day cleared the way for the Pacific Northwest rivals to join the league next year, and the Ducks were first to make it official with a brief video call that ended in a unanimous vote by the school’s 13 trustees. The Big Ten a short time later said its presidents’ council had voted to accept the Ducks along with Washington.

“Our student-athletes will participate at the highest level of collegiate athletic competition, and our alumni, friends, and fans will be able to carry the spirit of Oregon across the country,” Oregon President John Karl Scholz said.

The Big 12, meanwhile, has three more Pac-12 schools in its sights, a week after luring away Colorado.

A person with direct knowledge of the situation told The Associated Press that Arizona’s application to join the Big 12 was approved Thursday night. Arizona State and Utah, after it became apparent that Oregon and Washington were bolting the Pac-12 early Friday, also asked to join the Big 12.

The person spoke on condition of anonymity because the Big 12 and the schools were not making their internal discussions public.

The Big 12 presidents were scheduled to vote later Friday on Arizona State and Utah, and expected to approve the new members to become a 16-team conference next year.

Utah’s board of trustees met briefly Friday night and authorized the university president to approve a move to the Big 12. The Arizona board of regents met Thursday with the presidents of both schools and does not need to give final approval of a conference move for the Wildcats and Sun Devils.

All that was left was for the Big 12 to make their additions official.

The Pac-12 is now down to four members beyond this year: Stanford, California, Oregon State and Washington State.

The Big Ten’s latest grab from its Rose Bowl partner conference comes a little more than a year after it landed Southern California and UCLA. The moves give the sprawling Big Ten 18 member schools, including four on the West Coast. The Big Ten will be the largest conference in major college sports, spanning 15 states from New Jersey to Washington.

“The Big Ten is a thriving conference with strong athletic and academic traditions, and we are excited and confident about competing at the highest level on a national stage,” Washington President Ana Mari Cauce said.

Former Big Ten Commissioner Kevin Warren had encouraged member schools to consider adding Oregon and Washington after the conference landed the two Los Angeles schools last summer, the blow that has sent the Pac-12 reeling for more than a year. Colorado will join the Big 12 in 2024.

It has all left the storied Conference of Champions that dates back more than a century on the brink of extinction.

Pac-12 leaders met early Friday to determine if its remaining schools, which at the time included Oregon and Washington, would accept the potential media rights deal with Apple that Commissioner George Kilavkoff presented earlier this week, according to a person familiar with that meeting who spoke with The Associated Press on condition of anonymity because the details are private.

Two people with knowledge of the discussion between the Big Ten and Oregon said the Ducks were leaning toward staying in the Pac-12 late Thursday, boosting the possibility that others would stay put, too. Instead, Oregon officials notified the Pac-12 early Friday they were still uncomfortable with the Apple deal and the school would be re-engaging with the Big Ten.

The Pac-12 and Kliavkoff have made no public statements since Colorado’s announcement last week that it was rejoining the Big 12.

“We are disappointed with the recent decisions by some of our Pac-12 peers,” Washington State President Kirk Schulz and athletic director Pat Chun said Friday before its Apple Cup rival announced it was leaving, “While we had hoped that our membership would remain together, this outcome was always a possibility, and we have been working diligently to determine what is next for Washington State athletics. We’ve prepared for numerous scenarios, including our current situation.”

Less than two weeks ago, Big Ten Commissioner Tony Petitti said his presidents and chancellors wanted to him to focus on USC and UCLA’s transition to the Big Ten and not more expansion. Now, the Pac-12’s two biggest remaining brands and perennial football powers are heading for a new home. Their closest conference neighbor, the University of Nebraska, will be more than a 1,600-mile drive away.

Oregon and Washington will receive a reduced payout, Scholz confirmed, compared to current Big Ten members and to USC and UCLA, which are projected to receive more than $60 million each in media rights revenue from the league starting next year. A person familiar with the negotiations said the Ducks and Huskies would receive about $30 million per year for its first six years in the conference, with annual escalators and the ability to draw on future payments.

Washington was a charter member of the Pacific Coast Conference in 1916, the organization that eventually became the Pac-8, then 10, then 12. Oregon joined what was then the Athletic Association of Western Universities in 1964. USC’s history in the league dates to 1922, UCLA’s to 1928.

While the USC and UCLA decisions to leave started the Pac-12’s demise, last fall’s move by the Big 12 to get an early extension of its media rights deals with ESPN and Fox was key.

That left a thin market for Kliavkoff and the Pac-12, which ended up with the streaming-heavy proposal with Apple that would have left its schools lagging behind other Power Five conferences in revenue.