(CNN) -- The Iranian parliament Sunday voted to expel the British ambassador and reduce diplomatic relations with the nation in retaliation for newly-imposed Western sanctions, according to Iran's official news agency.
A majority of lawmakers voted to reduce diplomatic relations and economic ties and to expel the ambassador, IRNA reported.
The vote must go to the Guardian Council for approval.
The British Foreign and Commonwealth Office called the Iranian parliament's vote Sunday "regrettable."
"This unwarranted move will do nothing to help the regime address their growing isolation or international concerns about their nuclear program and human rights record," the office said in a statement. "If the Iranian government acts on this, we will respond robustly in consultation with our international partners."
Britain cut all financial ties with Iran last week over concerns about Iran's nuclear program, the first time it has cut an entire country's banking sector off from British finance, the British Treasury announced.
Last week all British credit and financial institutions were ordered to end their business relationships and transactions with all Iranian banks, their branches and subsidiaries by Monday.
The move came after an International Atomic Energy Agency report highlighted new concerns about "the possible military dimensions of Iran's nuclear program," the Treasury statement said Monday.
"The IAEA's report last week provided further credible and detailed evidence about the possible military dimensions of the Iranian nuclear program," British Foreign Secretary William Hague said in a statement Monday. "Today we have responded resolutely by introducing a set of new sanctions that prohibit all business with Iranian banks."
Iran insists its nuclear program is peaceful and has called the U.N. watchdog's report "unbalanced" and "politically motivated."
The British sanctions underline "the severity of the government's concerns about Iran's activities," Britain's chancellor of the exchequer said.
The chancellor's statement said other "partner countries" will make similar announcements about banking sanctions against Iran.
Iran's proposal mandates the foreign ministry to adopt similar positions against countries that adopt the same policies as Britain, the news agency reported.
CNN's Mitra Mobasherat contributed to this report.