Newcastle striker Papiss Cisse has pulled out of the club's pre-season tour over the club's new shirt sponsor.

The Senegalese striker is refusing to wear the logo of money lending company Wonga on religious grounds.

Cisse is a Muslim, and according to his religion, the lending of money for interest is forbidden.

The 28-year-old forward has offered to wear an unbranded shirt or one bearing a charity logo instead.

But sources at the club describe the situation as "strained" with doubts cast over his Magpies future.

However fellow midfielder Chiekh Tiote, also a Muslim, has chosen to wear the shirt with the Wonga logo.

There are previous cases involving shirt sponsors and religious beliefs.

Former West Ham striker Freddy Kanoute, a convert to Islam, objected to wearing a shirt bearing the logo of 888.com during his time at La Liga club Sevilla. 

However, Kanoute eventually wore the sponsored shirt but was excused from any promotional work with the gambling website.