The United States is on high alert for terror attacks while Iran is suspected of eyeing up ways to "extract revenge" for strikes.
Since the start of the Iran war, several terror-related incidents have occurred across America - and leading counter-terror authorities have expressed concern about attacks in the US.
They have pinpointed the Fifa World Cup, being hosted by the US, Mexico and Canada, as a potential target for vengeful US opponents in just a matter of months.
Dr Matthew Levitt, counterterror expert who once served in the FBI and Treasury Department told The Telegraph the Islamic regime would want revenge for the assasination of former Supreme Leader Ali Khamenei.
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The slain Ayatollah's burial is currently in the works, internal documents drawn up by Iranian officials revealed earlier in April.
Dr Levitt further warned: "It would not be surprising for Iran to just pull out all the stops."
The FBI guru mused that even the current ceasefire would not ease simmering tensions within America with unhappy pro-Iranian regime fanatics.
He added the peace deal, announced last week, "likely lowers the immediate threat levels" just for a finite amount of time.
An expert said Iran would try to 'extract revenge' for strikes
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"Should the ceasefire collapse, we’re back to where we were," he forecast.
"And if it succeeds, it’s only a matter of time before Iran seeks to exact revenge for the damage America and Israel inflicted."
Last month, a man who was suspected of smashing a vehicle filled with explosives into a Michigan synagogue had relatives who died in an Israeli air strike on his homeland, in Lebanon.
Ayman Mohamad Ghazali, who suffered "devastating and personal losses overseas", was shot dead by authorities after he conducted the horrific attack.
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Ayman Mohamad Ghazali opened fire at a Michigan synagogue in March
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The Israeli Defense Forces have claimed his brother, who also died, was a Hezbollah commander.
After the bomb killed his loved ones, the "grieving" terrorist splashed £1,600 on fireworks and purchased a gun, going on to research Jewish-linked groups and bodies in the state.
FBI chiefs confirmed the vile attack was an "act of terrorism purposely targeting the Jewish community".
They further claimed three other attacks could be identified as terror attacks, all of which took place across America since the war broke out.
Last week, Donald Trump announced the two-week ceasefire between Washington and Tehran - including the reopening of the Strait of Hormuz.
However, the President became increasingly frustrated with Iran's decision to charge vessels passing through the key maritime passageway, until the Republican announced he would launch a blockade on the waterway himself on Sunday.
On the blockade's opening day, China defied Mr Trump by sending one of its tankers through the strait while slamming the US move as "dangerous and irresponsible".
The vessel, called Rich Starry, sailing under the Malawi flag is owned by Shanghai Xuanrun Shipping Co Ltd.