CHINA warned the US against opening a “Pandora’s box” in the Middle East today after Washington announced it was mobilising 1,000 extra troops to the region as it ratchets up pressure on Iran.

Beijing’s Foreign Minister Wang Yi told reporters at a joint press conference with his Syrian counterpart Walid Muallem that the US in particular should “change its practice of extreme pressure.”

“We call on all parties to remain rational and restrained, not to take any actions to provoke the escalation of tension in the region and not to open a Pandora’s box,” he said.

Mr Wang also urged Tehran not to abandon the nuclear deal “so easily” after it announced that its stockpiles of uranium would increase beyond agreed limits by June 27 unless European countries helped Iran to beat US-imposed sanctions.

Washington blames Iran for the attack on two oil ships in the Gulf of Oman last week.

Doubts remains over the claims which Iranian Foreign Minister Javad Zarif claimed was a US attempt to sabotage democracy.

Mr Zarif warned that blaming Iran for the attacks was an attempt to “cover up [US] economic terrorism … without a shred of factual or circumstantial evidence.”

It came amid talks between Iran and Japanese Prime Minister Shinzo Abe in an attempt to mediate between the two countries.

Tokyo is refusing to back US claims of an Iranian attack, saying it needs to see more credible evidence.

Chief cabinet secretary Yoshihide Suga said at a press conference on Monday: “We can’t make any statement based on a presumption.”

Yutaka Katada, president of the Kokuka Sangyo shipping company, insisted claims that his company’s oil tanker was attacked by Iranian mines were false.

“The crew is saying that it was hit by a flying object,” he said. “To put a bomb on the side is something that we are not thinking.”

The US released another grainy photograph yesterday which it claimed showed Iran’s Islamic Revolutionary Guard Corps removing an unexploded mine from the Japanese vessel.

“Iran is responsible for the attack based on video evidence and the resources and proficiency needed to quickly remove the unexploded limpet mine,” the US Central Command said.

Critics have suggested that it would be a dangerous and brazen move due to the heavy US presence in the waters and the mission appearing to take place in broad daylight.

Iranian President Hassan Rouhani said on state television yesterday that his country wanted to avoid conflict.

“Iran will not wage war against any nation,” he said. “Those facing us are a group of politicians with little experience.”