Members of the Islamic Consultative Assembly Sunday approved a bill requiring the government to downgrade ties with Britain and expel British Ambassador Dominick Chilcott within two weeks, the semi-official Fars news agency said.
A statement issued by Britain's Foreign Office called the decision "regrettable," the BBC said.
The bill was approved by 179 legislators with 11 abstentions and four who opposed the vote demanding harsher steps be taken and all ties cut with London, Fars reported
The bill must be approved by Iran's Guardian Council, which vests all legislation before it can take effect, the BBC said.
The decision comes just days after Britain and the United States imposed harsh financial sanctions on Tehran to halt its nuclear program. The British Treasury imposed sanctions on Iranian banks, accusing them of facilitating the country's nuclear program, the BBC said.