Amir Khan is keeping his options open as he searches for one last opponent before making the step up to welterweight.

Khan, the WBA and IBF light-welterweight champion, wants to fight in the 147-pound category after he turns 25 in December and has his sights set on a potential showdown with Floyd Mayweather next year, but is first looking to sign off in style with a "big" final bout in his current division.

Lamont Peterson became mandatory challenger for the IBF belt after defeating Victor Cayo last week, although Khan says the American has turned down offers to face him in the past.

The Bolton fighter also recently claimed Timothy Bradley was "scared" to take him on.

Bradley, the WBO champion who has been stripped of his WBC title, has already pulled out of the contest once after verbally agreeing to it, with Khan coming up against Zab Judah instead last month and securing the IBF crown with victory inside five rounds.

Another name frequently mentioned as a possibility is Mexico's Erik Morales, who is set to battle Lucas Matthysse for the now-vacant WBC belt in September.

"We offered a fight against Peterson about six months ago and they have always turned us down," Khan told Press Association Sport.

"They never wanted to fight and now he is the mandatory, we will see how much he wants it.

"I'm ready to fight everyone in the 140-pound division, it is just that they don't want to fight me.

"I'm thinking only one more fight, but I want to make it a big fight. We are still trying for Bradley and we hope he signs.

"If Morales becomes the new WBC champion, I'd love to take that fight because I just want to keep on collecting titles.

"Morales said he would fight me if he thinks it is the right time, and maybe it is the right time."