The MV Mercer Street, operated by an Israeli-owned firm, was attacked off Oman on Thursday.
A British national and a Romanian citizen were killed.
The incident appears to be the latest escalation in an undeclared “shadow war” between Israel and Iran.
On Monday, Middle East minister James Cleverly summoned Iranian diplomat Mohsen Baharvand to a meeting at the Foreign Office to discuss the issue.
Israel’s Prime Minister Naftali Bennett said there was “evidence” that its longstanding foe Iran was responsible.
Mr Bennett warned that “we know how to send a message to Iran in our own way”, while Tehran rejected what it called the “baseless accusations”.
In a statement on Sunday, UK Foreign Secretary Dominic Raab said London believed Iran had used one or more drones against the MV Mercer Street, calling it “deliberate, targeted, and a clear violation of international law”.
“Iran must end such attacks, and vessels must be allowed to navigate freely,” he added.
Meanwhile, Lisa Nandy, Labour’s shadow foreign secretary said: “This reckless Iranian attack on a merchant vessel in international waters is a flagrant breach of international law.
“It is tragic that this has led to the death of two sailors, including one Briton. We send our deepest condolences to their families.
“The Prime Minister must make it clear to the incoming Iranian President that lawless actions will carry costs. This is the moment where Britain must show we are resolute in our determination to end this pattern of behaviour.
“The breakdown of a clear strategy to deal with Iran has not served the UK or our allies well in recent years. The Foreign Secretary must now make it a priority to pursue coordinated international efforts to tackle these actions by the Iranian Government.”
Israel’s PM has said it expected the international community to make clear to Iran that it had made a serious mistake.
Responding to accusations that Iran was responsible for the attack foreign minister Saeed Khatibzadeh, told reporters that “the Zionist regime (Israel) has created insecurity, terror and violence”.
He said Israel “must stop such baseless accusations”, warning: “Whoever sows the wind reaps the whirlwind.”
Thank you for helping to make Jewish News the leading source of news and opinion for the UK Jewish community. Today we're asking for your invaluable help to continue putting our community first in everything we do.
Unlike other Jewish media, we do not charge for content. That won’t change. Because we are free, we rely on advertising to cover our costs. This vital lifeline, which has dropped in recent years, has fallen further due to coronavirus.
For as little as £5 a month you can help sustain the vital work we do in celebrating and standing up for Jewish life in Britain.
Jewish News holds our community together and keeps us connected. Like a synagogue, it’s where people turn to feel part of something bigger. It also proudly shows the rest of Britain the vibrancy and rich culture of modern Jewish life.
You can make a quick and easy one-off or monthly contribution of £5, £10, £20 or any other sum you’re comfortable with.
100% of your donation will help us continue celebrating our community, in all its dynamic diversity...
Being a community platform means so much more than producing a newspaper and website. One of our proudest roles is media partnering with our invaluable charities to amplify the outstanding work they do to help us all.
There’s no shortage of oys in the world but Jewish News takes every opportunity to celebrate the joys too, through projects like Night of Heroes, 40 Under 40 and other compelling countdowns that make the community kvell with pride.
In the first collaboration between media outlets from different faiths, Jewish News worked with British Muslim TV and Church Times to produce a list of young activists leading the way on interfaith understanding.
Royal Mail issued a stamp honouring Holocaust hero Sir Nicholas Winton after a Jewish News campaign attracted more than 100,000 backers. Jewish Newsalso produces special editions of the paper highlighting pressing issues including mental health and Holocaust remembrance.
In an age when news is readily accessible, Jewish News provides high-quality content free online and offline, removing any financial barriers to connecting people.
Voice of our community to wider society
The Jewish News team regularly appears on TV, radio and on the pages of the national press to comment on stories about the Jewish community. Easy access to the paper on the streets of London also means Jewish News provides an invaluable window into the community for the country at large.
We hope you agree all this is worth preserving.