"We are pleased to partner with you in Poland's national defence," US Vice President Mike Pence said in Warsaw as the deal was inked in an air hangar filled with Polish and US troops.

It means that "Poland is taking its place among the most capable and formidable nations in the world," he said, underscoring strong US ties with its NATO ally.

His comments were echoed by Polish President Andrzej Duda, who has lobbied Washington hard for a permanent US military presence in Poland.

The purchase will help strengthen "the defense potential of Poland and the Polish army but will also increase security in our part of Europe, on the eastern flank of the Atlantic Alliance," Duda said.

The first stage of the acquisition of "20 HIMARS systems" will go ahead in 2023, he said.

Pence and US Secretary of State Mike Pompeo are headlining a conference in Warsaw on security issues in the Middle East on Wednesday and Thursday that the US is co-hosting with Poland.

Made by US weapons giant Lockheed Martin, the HIMARS system can launch six guided rockets with a range of 70 kilometres (37 miles), or a single missile with a 300-kilometre range.

- Increased US presence -

It is already being used by 19 countries including the US and has been deployed in Iraq and Syria against the Islamic State group, allowing US troops a precision attack ability even in poor weather when air attacks are hindered.

In March last year, Warsaw signed a $4.75 billion contract to purchase a US-made Patriot anti-missile system.

Poland's rightwing government has been pushing for the US to open a permanent military base on its soil, where nearly 5,000 American troops are already stationed on a rotational basis as part of NATO operations.

Pence confirmed later on Wednesday that "our two countries are discussing the parameters for an increased United States military presence in Poland" without going into detail.

He told Duda that he would be "carrying back your strong convictions regarding that to President Trump."

Pompeo told reporters visiting a US-led NATO battalion in northern Poland on Wednesday that Washington would "make sure" to have the "right" number and "mix" of troops in Poland in future without indicating when a decision could come.

Earlier on the same day, US ambassador Georgette Mosbacher told the Financial Times that a troop boost would be "significant" and would pass the "hundreds mark".

The US leads a multinational NATO battalion in Poland, one of four the alliance deployed to the region in 2017 to act as tripwires against possible Russian adventurism in the wake of Moscow's 2014 annexation of Crimea from Ukraine.

mas/pma

LOCKHEED MARTIN