The US has pledged £1bn in assistance to Colombia, after the country’s new right-wing president was sworn in on Friday.

Trump ally Abelardo de la Espriella used his maiden speech to promise an “all-out war” on what he calls “narco-terrorism”.

In a statement hailing a “new era in US-Colombia relations”, the US state department announced the financial support as part of a “security package” to help de la Espriella achieve “our shared goals”, which include fighting organised crime and illegal immigration.

The new president’s inauguration marks a dramatic shift to the right for Colombia, as he replaces the left-wing former leader Gustavo Petro, who frequently clashed with Trump.

Trump endorsed de la Espriella during the election, and said he predicted a “much better relationship” with his new counterpart after his victory in June.

A US delegation led by then-acting Attorney General Todd Blanche, who has since been confirmed to the post, attended the inauguration. It was also attended by embattled Fifa president Gianni Infantino.

De la Espriella chose to take the oath of office not in Colombia’s capital, Bogotá, but in the volatile city of Cali, in the west. The change was intended to signal a tough approach to illegal armed groups operating in the region.

In his fiery maiden speech – addressing troops at a nearby military base – de la Espriella pledged to crush armed insurgents, rebuild Colombia and defend democracy “by reason or by force”.

He said “in the age of the Tiger” – his self-appointed nickname – the state would be forceful and decisive against crime.

“There will not be a single place in our territory where criminals can feel safe,” he said.

The new president had a successful career as a lawyer representing drug-trafficking paramilitaries, footballers and fraudsters before entering politics. Critics have warned his confrontational style could deepen divisions in an already highly polarised country.

De la Espriella has vowed a sharp break with his left-wing predecessor. Instead of holding peace talks with armed groups, he has promised a brutal crackdown on their activities and the construction of mega-prisons.

He has also promised a strong military alliance with the US and Israel, in stark contrast to Petro, a long-time critic of Israel’s Prime Minister Benjamin Netanyahu.

In one of his first acts as president, de la Espriella said Colombia would join the “Shield of the Americas” security partnership founded by Trump.

The US welcomed this, and said it “stands ready to support the de la Espriella administration’s efforts to defeat the vicious narco-terrorist and criminal organisations” that threaten security.

The state department also said shared goals included halting illegal immigration through “closer coordination on border security”.

What Washington calls de la Espriella’s “pro-growth agenda” has created an opportunity to “increase trade and deepen economic ties between our countries”, it added.