Johnson's remark on Sunday came a day ahead of his meeting with Iranian President Hassan Rouhani here on the sidelines of the ongoing 74th session of the UN General Assembly (UNGA), the BBC reported.
Speaking on board an RAF Voyager jet on the way to New York, Johnson gave the UK's first attribution of blame.
"I can tell you that the UK is attributing responsibility with a very high degree of probability to Iran for the Aramco attacks."
Johnson said he would be working with the US and other European countries "to construct a response that tries to de-escalate tensions in the Gulf region".
Yemen's Iran-backed Houthi rebels have claimed responsibility, while Tehran itself has denied any involvement. It warned it would retaliate against any attacks after the US announced it was sending troops to Saudi Arabia.
Asked if military action was possible, he said: "We will consider in what way we could be useful if asked and depending on what the exact plan is."
Sanctions also remained on the table, Johnson added.
In his meeting with Rouhani, Johnson said that he would also bring up the case of Nazanin Zaghari-Ratcliffe and other dual British-Iranian nationals held in Tehran, the BBC reported.
Besides Rouhani, Johnson is slated to hold talks with Indian Prime Minister Narendra Modi, his Irish counterpart Leo Varadkar, US President Donald Trump, French President Emmanuel Macron and German Chancellor Angela Merkel, European Council President Donald Tusk, among other leaders.
( With inputs from IANS )