Military trainers will be sent to Jordan to help the nation's air force in the fight to take out Isis, Theresa May will announce during a visit to the Middle East.
In the wake of the Westminster terror attack, the Prime Minister will say the evil threat posed by the murderous jihadi group shows how allies must come together to face it down.
Arriving in the country's capital Amman, she will set out a package of measures to bolster cooperation between British forces and the Royal Jordanian Air Force (RJAF) and to tackle violent extremism in the region.
Jordan has stepped up its airstrikes against IS, also known as Daesh, in recent months and boosting military links with the nation will help keep Britain safe, the PM will say.
Under the plans, training will be carried out in Jordan and the UK to help the RJAF improve its capability to strike IS targets and defeat the terrorist threat.
During talks with King Abdullah just a month after they met in Downing Street, the premier will also discuss support for the state as it deals with the fall-out from the conflict in neighbouring Syria, which has forced hundreds of thousands of refugees to flee over the border.
The Prime Minister is also heading to Saudi Arabia during the three-day trip, which will focus on strengthening trade and security ties as Britain prepares to quit the European Union.
Ahead of the visit, she said: "It is clearly in the UK's security and prosperity interests to support Jordan and Saudi Arabia in tackling regional challenges to create a more stable region, and in delivering their ambitious reform programmes to ensure their own stability.
"An even deeper partnership with these countries, and greater knowledge and understanding of one another, will increase our ability to address the issues that concern us, including the promotion of international standards and norms.
"To tackle the threats we face from terrorism and from geopolitical instability, we must meet them at their source. Jordan is on the frontline of multiple regional crises and I'm clear that by working with them, we are helping keep British people safe.
"Likewise in Saudi Arabia: we must never forget that intelligence we have received in the past from that country has saved potentially hundreds of lives in the UK."
After her meetings in Jordan, Ms May will fly to Saudi Arabia, the UK's largest trading partner in the Middle East - with goods and services exports totalling £6.6 billion in 2015, where talks will focus on stronger ties following the vote for Brexit.
Mrs May has faced repeated calls to suspend arms sales to Riyadh amid claims of widespread human rights abuses in Yemen during the coalition bombing campaign it is leading, which includes Jordan.
The Saudis back the war-torn country's internationally recognised government against Iran-backed Houthi rebels.
Britain has continued to allow arms sales, with more than £3.3 billion of exports since the bombing began in March 2015. At least 10,000 people have been killed during the war, according to the United Nations.
Foreign Secretary Boris Johnson apologised at the weekend to the Saudi government after an activist tried to carry out a citizen's arrest of one of the Gulf state's generals.
An anti-war campaigner attempted to arrest Maj Gen Ahmed Asiri over Saudi Arabia's involvement in the conflict in Yemen - while another protester threw an egg at the senior officer as he arrived at an event in London.
Mr Johnson "expressed his regret" at the incident during a phone call with Saudi Deputy Crown Prince Mohammed bin Salman.
The visit to the kingdom also comes just days after the Government was pressed to explain why the state "consistently features in the back story of terrorists" - including the Westminster attacker.
Khalid Masood, the extremist who carried out the 82-second rampage on March 22, worked in the country for several years.
The Kent-born 52-year-old mounted the kerb twice as he sped across Westminster Bridge, killing three people and leaving dozens injured, before charging the Palace of Westminster grounds armed with two knives, killing Pc Keith Palmer.
