Did Iran hack water systems in seven US states?

Many were surprised last week when the US state of Minnesota reported that more than 30 of its state water systems had faced a "co-ordinated cyber-attack".

Days later the FBI warned cyber-attacks had been reported in seven states and "some of that activity degraded water operations".

Although US President Donald Trump has not blamed Iran, cyber-experts tell the BBC it's likely the attack was directed by Tehran.

Morgan Wright, a former US state department anti-terror adviser, told the BBC that these kinds of attacks are usually attributed to North Korea or Iran.

US investigators are also looking into whether the hackers could have posed as Iran-based as a ruse to sow further discord amid the US war with Iran, according to the BBC's US partner CBS.

Jake Braun, former acting White House Deputy National Cyber Director, told the BBC that the Trump administration is involved in its own information war and therefore it might be unlikely to admit that Iran did infiltrate US water infrastructure, even if it was confirmed.

At a cabinet meeting last Friday, Trump, a Republican, blamed "grossly incompetent" Minnesota officials, including Governor Tim Walz, for the water hack.

Walz, a Democrat, responded: "Trump knows exactly who is responsible for this attack, and knows that other states were hit too."

After a 2016 accusation linked to the targeting of banks and a dam outside New York City, Iran's foreign ministry spokesman said the US should prove such accusations.

Iran has "never had on its agenda any dangerous measures in cyberspace and does not support such moves", spokesman Hossein Jaberi Ansari said on state TV at the time.

Iran has a documented history of this kind of activity, experts told the BBC.

They noted that groups supportive of Iran, but located outside the country could be responsible.

"It makes it harder to assign attribution because if all of your attacks and groups are coming out of Iran, you can pretty much link it to Iran," Wright said.

He noted that such a tactic offers bad actors plausible deniability.

"They do it so that their fingerprints aren't directly on it," he said.

Most of the Iranian cyber-attacks against the US and Israel this year have been carried out by a group called Handala, BBC Verify has found.

The US justice department has linked the group to Iran, external, saying they have been working on behalf of the the Islamic Republic of Iran's Ministry of Intelligence and Security (MOIS).

Handala previously was accused of accessing some personal details and emails by FBI Director Kash Patel in the early days of the Ir