Ronaldo and Ramos
Football - Real Madrid v Juventus - UEFA Champions League Semi Final Second Leg - Estadio Santiago Bernabeu, Madrid, Spain - 13/5/15 Real Madrid's Cristiano Ronaldo celebrates with Sergio Ramos after he scores their first goal from the penalty spot Reuters/Juan Medina

Manchester United are on high alert after Real Madrid stars Cristiano Ronaldo and Sergio Ramos handed transfer requests to Real Madrid.

United have a chance to finally swoop their longtime targets Ronaldo and Ramos from the La Liga side after the Los Blancos duo requested a transfer from the Spanish giants, reports Spanish TV show El Chiringuito. The report, which was noted by several media outlets, revealed that Ronaldo and Ramos had spoken to club president Florentino Perez following Real’s 1-0 defeat against Atletico Madrid last month about a possible transfer at the end of the season.

There are no concrete numbers yet for how much it will cost United to bring Ronaldo and Ramos to the Premier League. But according to Oscar Mendez of Spanish gossip site Fichajes, translated by Yahoo Sports UK, the Red Devils are willing to offer at least £150 million (AU$288.3 million) for the pair, who have been key to Real’s recent success in La Liga.

Ramos was one of United’s targets last summer in a possible exchange of the club’s goalkeeper David De Gea, but the English side failed to sign the Spanish international after he committed to an extension with Real until 2020.

On the other hand, Ronaldo has long been linked to a return to Old Trafford, but Real has been able to keep hold of the two-time FIFA Ballon d’Or winner. The Portuguese football star admitted last month that he plans to play with Real for the next two years, but admitted he would consider other options once his contract expires in 2018.

"I want to stay here two more years. The two years I'm talking about take me to the end of my contract," Ronaldo said as quoted by Spanish newspaper AS. "And the future, we'll see."

Meanwhile, United could miss out on acquiring Napoli striker Gonzalo Higuain after reports that English Premier League rivals Liverpool were willing to offer the Argentine international £62 million (AU$119 million), according to the Daily Star.

But United is not the only team facing competition for Higuain, with Arsenal and Chelsea also reportedly set to bid for the 28-year-old striker.