The UK will pursue closer economic ties with the European Union in light of the war in Iran, Sir Keir Starmer has said.
The prime minister told a news conference he would use a summit with the EU later this year to seek more cooperation with the bloc on the economy and security.
It comes as relations between the US and the UK have been increasingly strained by the PM's refusal to be drawn further into the war with Iran.
In his speech, Sir Keir warned the conflict would impact the UK but sought to reassure the public the government was taking action to ease the cost of living.
The PM is facing calls from opposition parties to set out now how the government plans to protect people from rising energy costs.
The Conservatives and Reform UK are both calling for VAT to be taken off household energy bills, while arguing the hike in fuel duty scheduled for September should be cancelled.
The Liberal Democrats are also calling for the increase not to go ahead, while the Greens say the government should commit billions of pounds now to subsidise energy bills from July, when the price cap is recalculated.
Plaid Cymru said the government should set out now what support would be available if energy bills rise, while the SNP argues Holyrood should control energy policy.
Sir Keir said: "No matter how fierce this storm we are well-placed to weather it and we have a long-term plan to emerge from it a stronger and more secure nation."
He highlighted a number of measures coming into force from this month aimed at easing the cost of living, including removing some green levies from energy bills and increasing the national living wage.
The prime minister insisted the government had been "ahead of the game" in its focus on the cost of living.
However, the Organisation of Economic Co-operation and Development has warned the UK is facing the biggest hit to economic growth from the war out of major economies.
Asked if he would reassure motorists that the increase in fuel duty would not go ahead, Sir Keir said the rate remained set until September.
He added that support for households would be kept under review but "a lot will depend on how long the conflict goes on" and how quickly the Strait of Hormuz can be reopened.
Meanwhile, the foreign secretary is hosting a virtual meeting of 35 nations - including European and Gulf countries - on Thursday.
The PM said the meeting would discuss possible measures to make the Strait of Hormuz "accessible and safe after the fighting has stopped".
He added that "this will not be easy" but said it was in the UK's national interest for the strait to reopen.
Iran has effectively blocked the strait - one of the world's busiest oil shipping channels - leading to soaring wholesale oil and gas prices.
A sustained rise in the price of oil is likely to lead to a jump in household energy bills in the UK, when the current cap is reset in July.
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The PM and Chancellor Rachel Reeves have made a number of interventions in recent months arguing for a closer trading relationship with the EU.
However, Sir Keir argued that this was more urgent because of the impact of the US-Israel conflict with Iran.
"It is increasingly clear that as the world continues down this volatile path, our long-term national interest requires closer partnership with our allies in Europe and with the European Union," he said.
He added that Brexit "did deep damage to our economy" and "the opportunities to strengthen our security and cut the cost of living.... are simply too big to ignore".
A UK-EU summit is expected this summer, after the two sides struck a deal last May on areas including fishing rights, trade, defence and energy.
Sir Keir said this year's summit "will not just ratify existing commitments made at last year's summit" but would be "more ambitious".
The PM was asked if the UK was heading towards rejoining the EU single market, which enables goods, service and people to move freely between member states, with countries applying many common rules and standards.
"I do think that we should strengthen our cooperation on defence, security, energy, emissions and the economy," he replied.
"I'm ambitious that we can do more in relation to the single market, because I think that's hugely in our economic interests."
However, he said Labour's election manifesto commitment that there would be no return to the single market, the customs union or freedom of movement remained.
The Liberal Democrats have called for the government to go further and negotiate a customs union - an agreement not to charge taxes called tariffs on goods coming from other EU countries, and to charge the same tariffs as each other on goods coming from outside the EU.
Meanwhile, the Conservatives accused the PM of blaming his failings on Brexit.
Pressed over whether he was choosing Europe over the US, Sir Keir insisted: "I'm not going to choose because I think it's in our interest to have a strong relationship with the US and with Europe."
He argued that closer ties with Europe would strengthen the UK's relationship with the US as well, since successive US presidents had been pushing for Europe to do more on defence and security.
President Donald Trump has repeatedly criticised Sir Keir in recent weeks, following his refusal to allow the US to use UK bases for its initial offensive strikes against Iran.
The UK has since given permission for its bases to be used for defensive action against Iranian missile strikes.
In his latest comments, Trump told the Daily Telegraph he was considering pulling out of the Nato military alliance with European countries after they did not join his war in Iran.
Asked about the remarks, Sir Keir said the UK was "fully committed to Nato", which he described as "the single most effective military alliance the world has ever seen".
He added: "Whatever the pressure on me and others, whatever the noise, I'm going to act in the British national interest in the decisions that I make.
"That's why I've been absolutely clear that this is not our war and we're not going to get dragged into it."
Meanwhile, Reeves told BBC Radio 2 she was "angry" Trump had chosen to go to war in the Middle East, without a "clear plan of how to get out".
She said the conflict was "causing real hardship".
DW Arabic 
