The UFC is targeting a lightweight championship bout between Khabib Nurmagomedov and Tony Ferguson -- a matchup the fight world has waited years to see -- in April.

The promotion is looking to book Nurmagomedov against Ferguson as the main event for a pay-per-view on April 18 inside Barclays Center in Brooklyn, UFC president Dana White told ESPN.

Contracts have not been signed, but both sides have expressed interest in the title fight pending further negotiations, sources told ESPN.

If the bout does become official, it will mark the fifth time Nurmagomedov (28-0) and Ferguson (25-3) have been scheduled to meet, dating back to 2015. The matchup has been canceled every time for various reasons. Nurmagomedov withdrew in 2015 and 2017, due to injury and weight issues. Ferguson pulled out in 2016 and 2018 due to injuries.

Nurmagomedov, of Dagestan, has a 12-0 record in the UFC, including two title defenses. Ferguson, of Southern California, is on a 12-fight win streak in the UFC.

In an interview with ESPN earlier this year, Nurmagomedov said he believed a matchup against Ferguson was the "most important fight in UFC," regardless of weight class. The 31-year-old champion is coming off a third-round submission win over Dustin Poirier in September.

Ferguson, 35, is coming off a second-round TKO against Donald 'Cowboy' Cerrone at UFC 238 in June. A former interim titleholder, Ferguson was scheduled to face Nurmagomedov in April 2018, but suffered a serious knee injury after he tripped on a cable during a studio interview promoting the fight.

Nurmagomedov and Ferguson are the No. 1 and No. 6 pound-for-pound fighters in the world, according to ESPN.