The permanent members of the U.N. Security Council, along with Germany, meet today in London to discuss tougher sanctions on Iran.
The meeting comes after confirmation that Tehran had ignored a deadline to halt uranium enrichment and instead expanded its nuclear program.
A British official says diplomats will discuss options for further sanctions, including reducing export credits that Iran receives from Europe and placing restrictions on arms exports.
The official says the aim is to use negotiations to get Iran to cooperate and suspend parts of its nuclear program.
The U.S. and its European allies fear that Iran will use it's program to develop a bomb.
Iran says the program is used strictly to produce energy, but has refused to end uranium enrichment, which is a possible pathway to nuclear arms.