Britain said Monday it will seek to ban the political wing of Hezbollah, making membership of the movement or inviting support for it a crime, in a move that earned swift praise from the United States and Israel.
The decision follows outrage last year over the display of the Hezbollah flag, which features a Kalashnikov assault rifle, at pro-Palestinian demonstrations in London.
"Hezbollah is continuing in its attempts to destabilise the fragile situation in the Middle East," British interior minister Sajid Javid said in a statement.
"We are no longer able to distinguish between their already banned military wing and the political party. Because of this, I have taken the decision to proscribe the group in its entirety," he said.
The ban is subject to a vote in the British parliament this week.
Hezbollah is a Shiite militant movement established in 1982 during the Lebanese civil war.
Its capture of two Israeli soldiers in 2006 sparked a 34-day war in which 1,200 people were killed.
Israel's foreign minister welcomed Britain's decision and called for the United Nations to follow suit.
"I would like to praise the British government on the decision to recognise the entire Hezbollah organisation as a terrorist organisation," Israel Katz wrote on Twitter.
"In my upcoming meeting with the UN secretary-general in New York next week I will stress that the UN institutions should take a similar resolution."
US Secretary of State Mike Pompeo also commended the move and said it showed that "international unity to confront Iran's regime continues to grow".
"This Iran-sponsored terrorist group has American blood on its hands & continues to plot & carry out attacks in the Mideast, Europe & around the world," he tweeted.
The Hezbollah movement, now a major political party in Lebanon, holds three cabinet posts there.
But British Foreign Secretary Jeremy Hunt said in a statement any distinction between its military and political wings "does not exist".
"This (decision) does not change our ongoing commitment to Lebanon, with whom we have a broad and strong relationship," he added.
Lebanon's Foreign Minister Gebran Bassil said senior British officials had agreed the issue should not "impact on bilateral relationships between Lebanon and Britain".
Bassil, whose Free Patriotic Movement party is allied with Hezbollah in government, added it "will not have direct negative consequences on Lebanon because we are already used to this situation with other countries".
Britain's government is also banning Ansarul Islam, a jihadist group which emerged near the border between Mali and Burkina Faso in 2016, and the Group to Support Islam and Muslims (JNIM), which has sworn allegiance to Al-Qaeda in the Islamic Maghreb.
The country has 74 international terrorist organisations proscribed under the Terrorism Act 2000.