Flash floods have injured 20 people in northern Iran, after what officials described as the region's heaviest rains in a century, Iranian media reported.

The rains have battered the cities of Astara and Talesh, on the Caspian Sea coast near the border with Azerbaijan since Sunday, the reports said.

"Heavy rains ... have fallen over Astara which have not been seen in 100 years," Gilan province's head of crisis management Amir Moradi told the ISNA news agency on Monday.

Twenty people have been injured, the Mehr news agency reported.

In a Libyan hospital ward, trauma and grief mix with disbelief and anger among the survivors of the flood disaster that killed untold thousands in the devastated city of Derna.

A tsunami-sized flash flood crashed through the Mediterranean city, razing entire neighbourhoods, after two upstream dams burst amid torrential rains on September 10.

"Two years ago, the big dam already had leaks, even though it was only half full," Abdelqader al-Omrani, 48, told AFP from his hospital bed in Benghazi, the major city in the eastern part of Libya.

Three members of Iraqi Kurdistan's anti-terrorism forces were killed Monday in a drone strike that hit an airfield near Sulaimaniyah, the autonomous northern region's anti-terrorism services said in a statement.

"Unfortunately the bombing killed three of our Peshmerga comrades from the anti-terrorist services" and wounded three others, the statement said, without identifying those behind the attack.

The drone strike targeted anti-terror forces at the Arbat airfield, southeast of Sulaimaniyah, which is mainly used by crop-spraying aircraft.

The head of the United Nations nuclear watchdog on Monday urged Iran to reconsider its decision to deny access to top UN inspectors, telling AFP that failure to cooperate will carry severe consequences.

The International Atomic Energy Agency said Saturday that Iran had withdrawn accreditation from several inspectors, a move Teheran described as retaliation for "political abuses" by the United States, France, Germany and Britain.

"We have to ask them to review this decision," IAEA chief Rafael Grossi said in an interview with AFP.

Crowds of Iranian football fans gave Cristiano Ronaldo a rapturous welcome on Monday as his Saudi team arrived in Teheran for the first home-and-away club tie since the two countries resumed diplomatic relations.

Fans chanted the name of the Portuguese five-time world player of the year as he arrived with his Al Nassr teammates to face Iranian club Persepolis in the Asian Champions League on Tuesday.

The match will be the first since Tehran and Riyadh reached a China-brokered deal announced in March.

Following are key dates in the storied relationship between the United States and its arch-rival Iran since Washington pulled out of a landmark nuclear pact with Tehran in 2018.

- 2018: nuclear deal walkout -

After years of mounting concern over Iran's nuclear enrichment programme, world powers reach a deal with Tehran on sanctions relief in exchange for guarantees it will not build an atomic bomb.

Three years later, then president Donald Trump pulls the United States out of the deal and reapplies the financial pain.

Five Israeli tourists will stand trial next month for allegedly gang-raping a young Briton in the popular Cyprus holiday resort of Ayia Napa, a court ruled on Monday.

The five men, aged between 19 and 20, will appear before a criminal court on October 5, the Famagusta district court decided.

Police said the defendants face charges of rape, sexual coercion, forced sexual intercourse, sexual harassment, abduction and indecent assault against a woman.

It was long past midnight when Abdel Moneim Awad al-Sheikh awoke to desperate screams from outside his home in the Libyan city of Derna, only to find his building engulfed by surging flood waters.

"I took nothing but my glasses and cellphone and fled as the waters shook the iron doors like an earthquake," recounted the 73-year-old survivor of the deadly disaster.

He and his family managed to escape from the first floor and rush up the stairs of the multi-storey building as the raging waters tore away the front door and swept it into the darkness.

The United States and Iran on Monday swapped five prisoners each in one of the arch-foes' first deals in years as Tehran gained access to $6 billion in frozen funds.

The five Americans freed by Iran, including one held for eight years, flew out of Tehran in a Qatari jet, hours after the unblocked funds were deposited in accounts also managed by Qatar.

The freed prisoners walked in the setting sun on the tarmac and within hours a separate US government plane shuttled them to Washington, where some will undergo medical check-ups.

Flames gripped the Sudanese capital Sunday and paramilitary forces attacked the army headquarters for the second day in a row, witnesses reported, as fighting raged into its six month.

"Clashes are now happening around the army headquarters with various types of weapons," one Khartoum resident, who declined to be named, told AFP.

Other witnesses in southern Khartoum said they heard "huge bangs" as the army targeted bases of the Rapid Support Forces paramilitaries with artillery.