Labour shadow education secretary Angela Rayner - who has widely been tipped to enter the race for her party’s deputy leader role - said the Prime Minister needed to speak about the “escalating dangerous situation” in the Middle East.
Mr Johnson has been holidaying on the Caribbean island of Mustique with girlfriend Carrie Symonds.
Ms Rayner’s comments follow the US assassination of Qassem Soleimani, the commander of Iran’s notorious Quds Force, in Iraq. President Donald Trump said the general was planning fatal attacks against Americans.
The killing has led to speculation over how the Iranians might respond, with the country’s Supreme Leader Ayatollah Ali Khamenei declaring that “harsh retaliation is waiting”.
The PM must at least get off his Sun lounger to make some kind of statement on the US attack killing the senior Iranian general and the escalating dangerous situation between Iran and the USA. Leaving it to the hapless Dominic Raab will not suffice 😩— Angela Rayner 🌈 (@AngelaRayner) January 3, 2020
Foreign secretary Dominic Raab released a statement earlier today, which said: “We have always recognised the aggressive threat posed by the Iranian Quds force led by Qassem Soleimani.
“Following his death, we urge all parties to de-escalate. Further conflict is in none of our interests.”
Asked if a comment from the Prime Minister could be expected, the Downing Street press office told Yahoo News UK that the government’s response was being led by the Foreign Office.
Mr Johnson has visited the private island of Mustique to celebrate the New Year.
Mr Raab’s comments have been criticised by Labour’s shadow foreign secretary and leadership candidate Emily Thornberry.
“The Foreign Office’s call for restraint today is too little and far too late, in the wake of such a brazen, unlawful and provocative attack,” she said.
Soleimani was an influential and important commander for Iran who oversaw their involvement in the Syrian Civil War and conflict in Iraq.
He was in charge of the Quds Force, which the US has designated as a terrorist organisation.
In two tweets, President Trump said the commander was responsible for killing and injuring “thousands of Americans” and claimed he was also accountable for deaths in Iran, too.
General Qassem Soleimani has killed or badly wounded thousands of Americans over an extended period of time, and was plotting to kill many more...but got caught! He was directly and indirectly responsible for the death of millions of people, including the recent large number....— Donald J. Trump (@realDonaldTrump) January 3, 2020
....of PROTESTERS killed in Iran itself. While Iran will never be able to properly admit it, Soleimani was both hated and feared within the country. They are not nearly as saddened as the leaders will let the outside world believe. He should have been taken out many years ago!— Donald J. Trump (@realDonaldTrump) January 3, 2020
The Foreign Office has advised British people visiting Iran to avoid any rallies, marches or processions taking place during the three days of national mourning declared in the country.
“Rallies and marches are likely in cities across Iran, and could become angry,” advice on the Foreign Office website states.