LONDON -- British Prime Minister Keir Starmer announced on Tuesday that the country will increase its defence spending to 2.5 percent of gross domestic product (GDP) by 2027.

Speaking in the House of Commons, lower house of the parliament, ahead of his meeting with US President Donald Trump in Washington later this week, Starmer made the announcement in an unexpected statement.

"We will deliver our commitment to spend 2.5 percent of GDP on defence, but we will bring that forward so we reach that level in 2027," he told lawmakers. "And we will maintain that for the rest of this parliament."

Starmer said that this increase will amount to an additional 13.4 billion pounds (about $17 billion) in annual defence spending from 2027. Britain's current defence spending stands at about 2.3 percent of GDP.

The prime minister also said that Britain's defence spending will rise to 3 percent of GDP in the next parliament, subject to economic and fiscal conditions.

The North Atlantic Treaty Organization (NATO) and Britain's international allies can trust that the British government will "put our collective security first", Starmer said.

To fund the rise in defense spending, Starmer said the government will cut spending on development assistance from 0.5 percent to 0.3 percent of GDP in 2027.

"This is not an announcement I am happy to make," Starmer said, adding that Britain will continue to play a key humanitarian role in Ukraine, Gaza and other regions, as well as in tackling climate change, supporting global health and advancing vaccination efforts.

Britain had been planning to lay out a "pathway" to raise its defence pending to 2.5 percent of GDP via a strategic defence review in the spring. However, mounting pressure has forced the government to fast-track the plan, amid concerns that Europe could be sidelined by negotiations between the United States and Russia to end the Russia-Ukraine conflict.

On Monday night, French President Emmanuel Macron, who met Trump in Washington, said a truce between Ukraine and Russia could be agreed in the coming weeks.