LONDON — British Prime Minister Boris Johnson hit out at Iran on Monday, warning Tehran of consequences for its attack on an Israeli-managed tanker off the coast of Oman last week. Iran, has, however, strongly denied its involvement in the attack on the oil tanker Mercer Street, which is operated by an Israeli-owned company. “Iran should face up to the consequences of what they’ve done,” Johnson said while talking to reporters on Monday, adding: “This was clearly an unacceptable and outrageous attack on commercial shipping.” “A UK national died. It is absolutely vital that Iran and every other country, respect the freedoms of navigation around the world and the UK will continue to insist on that.” Earlier in the day, the UK’s foreign ministry summoned Iran’s ambassador to London to protest Tehran’s alleged attack on the Israeli tanker. A UK foreign ministry spokesperson said: "The Iranian Ambassador to the UK, Mohsen Baharvand, was summoned on Monday to the Foreign, Commonwealth & Development Office by the Minister for the Middle East, James Cleverly, in response to the unlawful attack committed on MV Mercer Street on July 29,” the UK government said in a press statement. "Minister Cleverly reiterated that Iran must immediately cease actions that risk international peace and security, and reinforced that vessels must be allowed to navigate freely in accordance with international law." On Sunday, British Foreign Secretary Dominic Raab also condemned the attack in a statement. “The UK condemns the unlawful and callous attack committed on a merchant vessel off the coast of Oman, which killed a British and a Romanian national. Our thoughts are with the friends and family of those killed in the incident,” Raab was quoted in a statement released by the UK government. “We believe this attack was deliberate, targeted, and a clear violation of international law by Iran. UK assessments have concluded that it is highly likely that Iran attacked the MV Mercer Street in international waters off Oman on July 29 using one or more unmanned aerial vehicles (UAVs).” The UK foreign secretary added: “Iran must end such attacks, and vessels must be allowed to navigate freely in accordance with international law.” Raab said that the UK is working with our international partners on a concerted response to this unacceptable attack. — With inputs from agencies