Key developments since the United States quit the 2015 Iran nuclear deal three months ago and reimposed sanctions:

- US walks away -Donald Trump pulls the United States out of the landmark nuclear pact between world powers and Iran on May 8, reinstating Washington's sanctions on Iran and companies with ties to the Islamic republic.

Pakistan's new government led by prime minister Imran Khan faces myriad challenges. The cricketing icon turned politician will have to make hard choices, and quickly.

Russia typically brushes off new U.S. sanctions. Not this time.

The Trump administration announcement of export restrictions in response to accusations Moscow used a nerve agent to poison a former Russian spy in Britain sent the ruble tumbling to a two-year low and drew a stern warning from its prime minister. While the initial sanctions may have a limited impact, a second batch expected within months could hit the Russian economy much harder and send already tense relations into a tailspin.

Relations between Turkey and the United States are at their lowest ebb in recent times, with President Donald Trump announcing Friday he had doubled steel and aluminum tariffs against the NATO ally, adding to the Turkish lira's downward spiral.

Gaza has since late March been the scene of massive protests and clashes between Palestinians and Israeli soldiers along the border with Israel that have cost more than 160 lives.

With US sanctions back in force Tuesday, here is a look-back over developments in the 90 days since President Donald Trump withdrew from a hard-won 2015 accord on Iran's nuclear programme:

- Washington walks away -Trump pulls the US out of the landmark nuclear pact between world powers and Iran on May 8, reinstating Washington's sanctions on Iran and companies with ties to the Islamic republic.

Five years since Iranian President Hassan Rouhani took office, here are country's key moments under his leadership:

A wave of US sanctions kicks in against Iran on Tuesday, cementing Washington's hard line against Tehran after President Donald Trump pulled out of the 2015 nuclear pact.

The president should still be basking in the World Cup victory that sparked tumultuous joy on the streets of France -- but instead, he heads off to his southern summer retreat on Friday weighed down by a damaging scandal.

For two weeks opponents have seized on revelations that former top aide Alexandre Benalla roughed up May Day protesters while wearing police insignia, and that Macron's office knew about it but didn't inform prosecutors.

President Donald Trump thanked North Korean leader Kim Jong Un for "fulfilling a promise" to return the remains of U.S. soldiers missing from the Korean War, as a U.S. military plane made a rare trip into North Korea to retrieve 55 cases said to contain remains.

Close to 7,700 U.S. soldiers remain unaccounted for from the 1950-53 Korean War, and about 5,300 of those were lost in North Korea.