PHILADELPHIA - British Prime Minister Theresa May warned America’s allies on Thursday that they must "step up" and play their role in global security, as she wooed Republican lawmakers ahead of a meeting with US President Donald Trump.

May won several standing ovations when she pledged her commitment to the "special relationship" between Britain and the United States at a Republican party meeting in Philadelphia.

But while echoing some of Trump’s concerns about the NATO military alliance, May also warned him against moving too close to Russian President Vladimir Putin, saying Washington’s approach should be to "engage but beware".

The prime minister will on Friday become the first foreign leader to meet with Trump following his inauguration last week, when they hold talks on post-Brexit trade at the White House.

Britain’s second female prime minister, the reserved daughter of a vicar, has outwardly little in common with the outspoken US billionaire and her trip has attracted controversy at home.

But May has expressed confidence in Trump’s commitment to the UK-US "special relationship", and told reporters on her plane that "sometimes opposites attract".

In Philadelphia, May met senior Republicans including House Speaker Paul Ryan and became the first foreign leader to address the party’s gathering.

In her speech, May echoed Trump’s warnings that the US would not pay for the world’s defense, saying: "They should not undermine the alliances that keep us strong by failing to step up and play their part."

However, while accepting the need for reform in NATO and other international institutions such as the United Nations, she said they were vital in encouraging cooperation on global threats such as terrorism and climate change.

’Joint responsibility’ 

May acknowledged rising tensions between the US and China, but said fears of the "eclipse of the West" would not come to fruition if Britain and the United States stood together.

She invoked the memory of Margaret Thatcher and Ronald Reagan working together in the Cold War.

"We -- our two countries together -- have a joint responsibility to lead.

Because when others step up as we step back, it is bad for America, for Britain and the world," she said.

In a reference to conflicts in Iraq and Afghanistan, she said: "The days of Britain and America intervening in sovereign countries in an attempt to remake the world in our own image are over.

"But nor can we afford to stand idly by when the threat is real and when it is in our own interests to intervene. We must be strong, smart and hard-headed."

May also defended the Iranian nuclear deal that Trump has denounced, although she said it should be "very carefully and rigorously policed."

Talking trade 

May is eager to start talks on a US-UK free trade agreement for when Britain leaves the European Union, which is also likely to mean leaving Europe’s single market and its 500 million consumers.

Trump has hailed the Brexit vote as "smart", believing it mirrors his own anti-establishment rise to the White House, but his calls for a protectionist trade regime could prove problematic for May.

Both London and Washington have expressed their interest in a quick trade deal, although under EU rules Britain must wait until it has left the bloc before it signs deals with any other states.

"There is much we can do in the interim, in terms of looking at how we can remove some of the barriers to trade in a number of areas," she told reporters on her plane. - AFP