WASHINGTON — President Trump on Friday said he will extend waivers on Iran sanctions, keeping the landmark 2015 nuclear deal alive for at least another several months despite his past vows to scuttle it. 

In a statement, Trump said this is the last time he will issue such waivers without addressing what he sees as four major weaknesses of the deal.

Trump issued the world an ultimatum: "Either fix the deal’s disastrous flaws, or the United States will withdraw."

The waivers will be accompanied by other, targeted sanctions on Iran and a stern warning that Trump will pull out of the deal negotiated by the Obama administration if fixes aren’t made by spring. 

That’s when the next deadline comes for extending sanctions relief for Iran.

Trump said he wants Congress to pass a bill requiring: 

-Timely, sufficient and immediate inspections at all sites by inspectors of the United Nations nuclear watchdog agency, the International Atomic Energy Agency (IAEA).

-That Iran remain above a 1-year timeline to secretly produce enough uranium for a bomb, called a "breakout period."

- Address the so-called sunset clause of the nuclear deal, which lifts some limits on Iran's nuclear program over time, by allowing the U.S. to reinstate sanctions without any expiration in case of Iran surpassing any of the limits set by the U.S. and its allies.

- And issue a statement that the U.S. and allies view Iran's long-range ballistic missiles and its nuclear program as inseparable, and that both must be curtailed if the deal is to remain in force.

Trump also said he wants to work with allies — but not with Iran — to enforce a similar approach, and to join the United States in pressuring Iran's Islamic Revolutionary Guard Corps, which conducts the country's military operations abroad, "and anyone else who contributes to Iran’s support for terrorism."

Those allies would be the United Kingdom, France and Germany, because they together with the U.S. had imposed the greatest sanctions on Iran before the Iran deal was reached, said an administration official who was not authorized to speak on the record.

Rep. Eliot Engel, D-N.Y., the ranking Democrat on the House Foreign Relations Committee, said Trump’s policy “sets impossible standards that would ultimately isolate the United States rather than isolating the regime in Tehran.”

The result would be for Iran “to rush headlong toward a bomb while harming American credibility and leadership,” Engel said. “I’m all in favor of trying to address the agreement’s weaknesses. But the way to do so is to engage with international partners and build momentum to negotiate new provisions. The wrong approach is to bully countries with arbitrary and unenforceable deadlines."

Trump’s waiver announcement also included harsh criticism of Iran’s response to recent protests against the Islamic Republic’s leadership.

Iran's government "props up the murderous regime of Bashar al Assad, and has helped him slaughter his own people," Trump said. "The regime’s destructive missiles threaten neighboring countries and international shipping. Within Iran, the Supreme Leader and his Islamic Revolutionary Guard Corps use mass arrests and torture to oppress and silence Iran’s people."

The U.S. is sanctioning 14 Iranian individuals over human rights abuses, freedom of speech in Iran and for proliferating weapons of mass destruction and ballistic missiles, the officials said.

Among those is Sadeq Larijani, the head of Iran's judiciary and brother of the speaker of Iran's parliament, Ali Larijani, showing that the U.S. is targeting Iran's top leadership, they said. Sadeq Larijani is being sanctioned for his responsibility over Iran's prison system, where inmates were executed who were juveniles at the time of their crimes, and where prisoners on hunger strike to protest inhumane conditions were tortured. At least one had his eyes gouged out by prison officials, according to U.S. officials who briefed reporters on background Friday because they were not authorized to speak on the record.

Other individuals on the list are involved in curtailing Iranians' freedom of assembly, and in blocking Iranians from content in cyber space that is critical of the government, including international sources, anti-regime sites, human rights, sites and social media. 

Contributing: Gregory Korte