UK Prime Minister Sir Keir Starmer has urged Iran to "refrain" from attacking Israel during a phone call with Iran's new president. Sir Keir told Masoud Pezeshkian there was a "serious risk of miscalculation and now was the time for calm and careful consideration", Downing Street said. It is the first call between a UK prime minister and an Iranian president since March 2021 when former British leader Boris Johnson spoke to Hassan Rouhani. News of the 30-minute discussion came as the UK issued a joint statement with the US, France, Italy and Germany — urging Iran to end its threats of an attack on Israel. They called on Iran to "stand down its ongoing threats of a military attack against Israel and discussed the serious consequences for regional security should such an attack take place". The leaders, who spoke together by phone, also expressed their support for the "defense of Israel against Iranian aggression and against attacks by Iran-backed terrorist groups". Fears of a wider conflict in the Middle East have been growing following the recent assassination of senior Hezbollah and Hamas leaders. On Sunday, the US confirmed it had sent a guided missile submarine to the region in response to these concerns. The submarine can carry up to 154 Tomahawk cruise missiles, which are used to strike land targets. It had also ordered the USS Abraham Lincoln carrier strike group, which is carrying F-35C fighter jets, to accelerate its journey there. The ship was already on its way to replace another US ship in the region. White House National Security Council spokesman John Kirby later said that the US shared Israel's concerns that it was "increasingly likely that there will be an attack by Iran and or its proxies and perhaps in the coming days". "That is why we have been continually speaking to our Israeli counterparts and other counterparts in the region," Kirby added. Rear Adm Daniel Hagari, a spokesman for the Israel Defense Forces (IDF), said that the country took the threats of its enemies seriously and that Israel was at "peak preparedness for attack and defence". Downing Street also said on Monday that Keir Starmer had told Pezeshkian he was "deeply concerned by the situation in the region and called on all parties to de-escalate and avoid further regional confrontation". Iran blames Israel for the assassination of Hamas leader Ismail Haniyeh on their soil late last month and has vowed to punish it. Israel, which is currently engaged in a war attempting to destroy Hamas in Gaza following the group's deadly attack on southern Israel on 7 October, has not commented but is widely believed to have been behind the killing. Iran's acting foreign minister said last week that the country would respond to the killing of Haniyeh at the "right time" in the "appropriate" manner. The Organization of Islamic Cooperation (OIC), a group of states with Muslim-majority populations, said it held Israel fully responsible for the attack, which it called "a serious infringement" of Iran's sovereignty. Ismail Haniyeh is not the only senior member of Hamas to be killed recently. Israel also recently announced that the group's military chief Mohammed Deif was killed in an air strike in the Gaza Strip last month. The Iranian-backed Lebanese group Hezbollah, with which Israel is also engaged in a conflict, has also said that it would retaliate for the death of its senior commander Fuad Shukr. Canadian Prime Minister Justin Trudeau on Monday became the latest leader to urge his country's citizens to leave Lebanon as soon as possible, warning of the risk of growing tensions. Airlines including Lufthansa, Swiss Air and EasyJet have either canceled or suspended flights to the Middle East. — BBC