Amir Khan and Manny Pacquiao are in talks over a potential fight this summer.
However it is understood each fighter is continuing to explore other options, and that negotiations are far from at an advanced stage.
Khan, 30, wrote on Twitter: "Currently negotiating with Manny. Coming soon. Watch this space."
What do think?
Currently negotiating with Manny #teampacquiao. Coming soon. Watch this space!— Amir Khan (@amirkingkhan) February 23, 2017
The 38-year-old Pacquiao added: "My team and I are in negotiations with Amir Khan for our next fight. Further announcement coming soon."
A fight against Pacquiao is one Khan has long sought and would prove lucrative, but he has felt misled in the past when his pursuit of a fight against either the Filipino or Floyd Mayweather has come to little.
As the mandatory challenger to the WBC welterweight title being contested by champion Danny Garcia and Keith Thurman next weekend, Khan is aware he remains in contention to face the winner.
He is also yet to rule out exploring a rematch with Lamont Peterson, to whom he lost controversially in December 2011, or an easier match-up after his last ended in a heavy knockout defeat by Mexico's Saul Alvarez.
The likelihood of Pacquiao fighting Australia's Jeff Horn - his favoured opponent earlier this year - appears increasingly unlikely, but has also not been entirely ruled out.
There were reports earlier this week that a verbal agreement was in place for a Pacquiao-Khan fight to take place in either Bolton or Manchester in May.
The United Arab Emirates, as opposed to Las Vegas or anywhere in the UK, would instead be the likely location, though negotiations have not progressed to the point of agreeing where any potential fight should take place.
Pacquiao's promoter Bob Arum, who earlier this week described talks of a fight between the two as "complete bull****", has since told ESPN: "Manny is trying to get a fight done in the United Arab Emirates.
"The people there favour him fighting Amir Khan.
"Whether it will happen or not I just don't know because they have to come up with a large amount of money.
"Manny seems to believe they will come up with the money. I have some reservations whether it will happen or not. If the money comes up I will aid and abet the fight happening."
Pacquiao continues to be trained by Freddie Roach but Khan left the American in September 2012 and is now under the tutelage of Virgil Hunter.