LONDON - British interior minister Suella Braverman will raise the "the unsustainable pressures" created by illegal migration when she makes a three-day visit to the U.S. this week, her office said on Sunday.

In a keynote speech, Braverman will present a blueprint for how countries can combat the crisis and highlight how Britain has led the way in bringing forward "innovative approaches" to tackling the issue, the Home Office said.

"Illegal migration and the unprecedented mass movement of people across the globe is placing unsustainable pressures on America, the UK and Europe," Braverman said in the statement.

"We must come together and ask whether the international conventions and legal frameworks designed 50-plus years ago are fit for purpose in an age of jet travel and smartphones."

British Prime Minister Rishi Sunak, who took office last year, has made "stopping the boats" - the arrival of migrants in small boats across the English Channel - a priority.

However, the UK government's policies, such as sending asylum seekers to Rwanda, have so far failed to take off. Almost 45,000 people were detected arriving by small boats in the 12 months to June, a 26% year-on-year rise, according to official data.

The Biden administration has also been grappling with high migration levels, with U.S. authorities encountering over 142,000 migrants at the U.S.-Mexico border in the first half of September.

Braverman, who will travel to Washington on Monday, will seek closer collaboration with the U.S. on addressing illegal migration and organised immigration crime. She will hold talks with lawmakers and senior U.S. officials, including Homeland Security Secretary Alejandro Mayorkas, the statement added.

"I'm going to Washington to discuss this (illegal migration) crisis with our American counterparts. If we fail to meet these challenges, then our political institutions risk losing their democratic legitimacy," Braverman said.

(Reporting by Muvija M; Editing by Mike Harrison)