WATCH: New UK PM Liz Truss pays tribute to Boris Johnson

Truss spoke to media from 10 Downing, where she said she had accepted Her Majesty the Queen's "kind invitation to form a new government."

Truss continued: "Let me pay tribute to my predecessor, Boris Johnson delivered Brexit, the Covid vaccine, and stood up to Russian aggression.

"History will see him as a hugely consequential prime minister.

"I'm honored to take on this responsibility at a vital time for our country. What makes the United Kingdom great is our fundamental belief in freedom, enterprise, and fair play," she said.

In her speech, Truss focused on three immediate priorities that she would tackle as prime minister.

According to BBC News, those areas are:

• The economy: Truss said she would focus on "getting Britain working again" with a "bold plan to grow the economy through tax cuts and reform." She said she would "cut taxes to reward hard work and boost business-led growth and investment" as part of her mission to "get the United Kingdom working, building and growing." She added that she would "make sure that we are building hospitals, schools, roads and broadband."
• Energy: Truss promised to "deal hands on with the energy crisis caused by Putin's war." She said she would "take action this week to deal with energy bills and to secure our future energy supply."
• The National Health Service (NHS): The PM said she would ensure that people could get doctors' appointments, and access to the NHS services they need. "We will put our health service on a firm footing," she said

US President Joe Biden congratulated Truss on Twitter after the conclusion of her speech, saying that he looks "Forward to deepening the special relationship between our countries and working in close cooperation on global challenges, including continued support for Ukraine as it defends itself against Russian aggression."