Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

Scotland’s leader announced Monday she will seek another referendum on independence from the U.K. as early as next year in response to Brexit, deepening the turmoil caused by Britain's decision to quit the European Union.

First Minister Nicola Sturgeon said she had encountered a “brick wall of intransigence” in dealings with the British government over the terms for withdrawal from the trading bloc.

She said the Brexit vote meant there had been a “material change in circumstances” since independence was rejected by Scottish voters by 55 percent to 45 percent in 2014.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

“The future of the U.K. looks very different today than it did two years ago,” she told reporters.

Sturgeon, who heads the pro-independence Scottish National Party, said she will seek the constitutional authority to hold another referendum in late 2018 or early 2019 — by which time the terms of Britain's withdrawal would be known.

It was not immediately clear if the Britain's ruling Conservative party, which is firmly opposed to independence, would veto her bid for a so-called "indyref2."

Related: Brexit Fans Flames of Secession in Scotland

Sturgeon said Scots should be allowed to choose "whether to follow the U.K. to a hard Brexit, or to become an independent country able to secure a real partnership of equals with the rest of the UK and our own relationship with Europe."

Scotland voted against Brexit in last June's referendum, preferring to remain in the EU. However, the U.K. overall voted to leave by 52 percent to 48 percent.

Scotland must have choice over future @ScotGovFM @NicolaSturgeon sets out plan for referendum in face of hard Brexit https://t.co/a9DPW2rmU8 — Scottish Government (@scotgov) March 13, 2017

Sturgeon said she had sought negotiations with British Prime Minister Theresa May over the details of Brexit but the U.K. government "has not moved even an inch in pursuit of compromise or agreement."

"Membership of the single market was ruled out with no prior consultation with the rest of the UK," she said. "We face a future outside the world's biggest single market."

Sturgeon said there was "warmth" in Europe at the prospect of Scotland being an independent member of the EU — although the mechanism for that prospect also remains unclear. The EU previously stated that an independent Scotland would have to apply to join the EU, rather than automatically being a member.

Sturgeon's announcement came as May was poised to invoke Article 50 of the Treaty of Lisbon, giving official notice of Britain's intention to quit the EU and starting the clock on up to two years of unprecedented negotiations.