US politics as it happened: China blocks journalists covering Wong; King Charles addresses US Congress; Trump says Iran in ‘state of collapse’

US President Donald Trump has attacked Germany’s Friedrich Merz after the chancellor earlier this week criticised the US handling of its war on Iran.

Merz said American negotiators were being “humiliated” by the Iranian leadership as the conflict, which has triggered global energy turmoil, approaches its third month.

“The Chancellor of Germany, Friedrich Merz, thinks it’s OK for Iran to have a Nuclear Weapon,” Trump wrote in a post on the Truth Social website on Tuesday. “He doesn’t know what he’s talking about! If Iran had a Nuclear Weapon, the whole World would be held hostage.”

The retort was delivered a day and a half after Merz weighed in with an unusually candid assessment of Trump’s negotiating strategy. Speaking to a group of students at a school in western Germany on Monday, the chancellor said he didn’t grasp the US exit strategy – and lauded Tehran’s negotiators for moving “very skilfully – or indeed very skilfully not negotiating”. An “entire nation is being humiliated by the Iranian leadership,” Merz said.

In one legislative chamber, a British king appealed to centuries of shared history in a bid to preserve his country’s most important alliance. In another, an ocean away, a British prime minister watched his agenda get sidelined again by his past efforts to protect the US-UK “special relationship”.

The twin scenes, playing out in Washington’s House of Representatives and the House of Commons in London, illustrated how much managing ties with Donald Trump’s America has come to consume the British state.

Despite Prime Minster Keir Starmer’s efforts to adapt his left-leaning Labour government to the billionaire Republican’s personality-driven foreign policy, he has watched ties sink to their lowest level in decades.

This week, Starmer deployed the best messenger he could muster to reach a president who is unusually comfortable associating himself with royalty: King Charles III.

Foreign Minister Penny Wong’s trip to Beijing on Wednesday – part of a flying visit through East Asia with stops in Tokyo and Seoul this week – could be well-timed.

China is signalling that it will resume exporting jet fuel, gas and diesel from May after heavily curtailing exports since the start of the Iran war to build up its own domestic supplies.

UK newspaper The Financial Times reported today that China’s largest state oil companies have applied for export permits to ship fuel in May, signalling that the de facto ban on exports may soon be lifted.

The US has warned banks they are at risk of secondary sanctions if they support Chinese private refiners that buy Iranian oil, cranking up pressure on Tehran even at the cost of further irking Beijing just weeks ahead of a leaders’ meeting.

Washington has been ratcheting up its efforts to cut off Iranian oil shipments, a vital financial lifeline. Last week, the Treasury Department sanctioned Hengli Petrochemical Refinery Co, one of China’s largest private oil refiners, targeting a large and well-connected player in the country’s vast crude-processing industry.

On Tuesday, the Treasury underscored the message by warning all banks supporting the Iranian trade would also be at risk.

“Financial institutions should be on notice that the department is leveraging the full range of available tools and authorities and is prepared to deploy secondary sanctions against foreign financial institutions that continue to support Iran’s activities,” it said in a statement.