The waiver he will sign suspends USA sanctions on Iran for another 120 days, BBC reports.
In July 2015, after a decade of strenuous negotiations, Iran and six major countries, namely, China, Russia, Britain, France, the USA and Germany, struck a final agreement on Iran's controversial nuclear programme.
In Brussels on Thursday, the European Union and the foreign ministers of Britain, Germany and France presented a united front after talks with Iranian Foreign Minister Mohammad Javad Zarif.
During that four-month period, he wants Congress and America's main European allies to draw up a new deal - without negotiating with Tehran - to replace the "disastrous flaws" in the current agreement.
While Trump approved the sanctions waiver, the Treasury Department announced new, targeted sanctions against 14 entities and people, including the head of Iran's judiciary, Sadeq Amoli Larijani, a close ally of Iran's Supreme Leader Ayatollah Ali Khamenei. Unilaterally re-imposing the sanctions would put the United States in violation of an worldwide agreement that was unanimously approved by the United Nations Security Council in 2015.
Trump said on Friday he would waive nuclear sanctions on Iran for the last time to give the United States and European allies a final chance to amend the pact. Trump is also waiving other US penalties covered by the agreement, including on Iran's oil and gas sectors, which were up for renewal next week. Mr. Trump is expected to decide by Friday whether to extend the sanctions relief or re-impose the restrictions his predecessor, President Barack Obama, suspended two years ago.
How to Watch the 2018 Australian Open Draw
His miserable year will see him seeded 14th, but Djokovic said he was "just grateful that I'm able to be here". I'm happy with the way it went today. "They're definitely two favourites to look at".
Trump will next have to deal with these decisions in mid-May.
The cyber unit of the Islamic Revolutionary Guard Corps, which the Trump administration maintains has stifled social media networks that demonstrators can use to communicate, was also blacklisted.
"So Trump now has issued explicit May deadline to Congress and Europeans: Fix Iran nuke deal or no more sanctions waivers", wrote Mark Dubowitz, head of the Foundation for Defence of Democracies.
"If at any time I judge that such an agreement is not within reach, I will withdraw from the deal immediately", he added.
"The Chinese side has also noticed that the global community widely supports the Joint Comprehensive Plan of Action (JCPOA), and fully acknowledges Iran's implementation of the pact, " Lu said.
Trump said that any legislation regarding Iran must demand worldwide inspections when requested at all sites, must ensure Iran doesn't come close to possessing a nuclear weapon, must not have any expiration date and must state that long-range missile and nuclear weapons programs are inseparable.