WEST PALM BEACH: President Donald Trump issued a stark warning to Iran on Saturday, threatening to hit dozens of targets in the Islamic Republic “very fast and very hard” if it retaliates for the targeted killing of the head of Iran's elite Quds Force.

The series of tweets came as the White House sent to Congress a formal notification under the War Powers Act of the drone strike on Gen. Qassem Soleimani, a senior administration official said. U.S. law required notification within 48 hours of the introduction of American forces into an armed conflict or a situation that could lead to war.

The notification was classified and it was not known if a public version would be released. House Speaker Nancy Pelosi said the classified document “suggests Congress and the American people are being left in the dark about our national security.”

In unusually specific language, Trump tweeted that his administration had already targeted 52 Iranian sites, “some at a very high level & important to Iran & the Iranian culture." He linked the number of sites to the number of hostages, also 52, held by Iran for nearly 15 months after protesters overran the U.S. Embassy in Tehran in 1979.

Thousands of Iranians lined Baghdad streets Saturday for the funeral procession for Soleimani. The Islamic Republic has vowed revenge for the Trump-ordered airstrike that killed him and several senior Iraqi militants early Friday Baghdad time.

Trump appeared to respond to such threats with tweets justifying Soleimani's killing and matching the bellicose language from Iran.

“Iran is talking very boldly about targeting certain USA assets as revenge for our ridding the world of their terrorist leader who had just killed an American, & badly wounded many others, not to mention all of the people he had killed over his lifetime, including recently hundreds of Iranian protesters,"the president tweeted. "He was already attacking our Embassy, and preparing for additional hits in other locations. Iran has been nothing but problems for many years.”

Trump also warned: "The USA wants no more threats!”

Trump’s reference to targeting sites “important to Iran & the Iranian culture” could raise questions about whether striking such targets would violate international agreements. The American Red Cross notes on its website that the Geneva Conventions of 1949 and their additional protocols, ratified by scores of nations in recent years, states that “cultural objects and places of worship” may not be attacked and outlaws “indiscriminate attacks on civilian populations.”

Democratic presidential candidate Joe Biden, campaigning in Iowa, questioned whether Trump was acting alone or with support of allies. “We have no idea – I have no idea – whether he has any plan at all,” the former vice president told reporters Saturday night. “But when he makes statements like that, it just seems to me to be he’s going off on a tweet storm on his own, and it’s incredibly dangerous and irresponsible.”

The notification document sent Saturday to congressional leadership, the House speaker and the Senate president pro tempore was entirely classified, according to a senior Democratic aide and a congressional aide. The aides and the senior administration official were not authorized to discuss the matter publicly and requested anonymity.

In a statement, Pelosi said the “highly unusual” decision to classify the document compounds concerns from Congress.

“This document prompts serious and urgent questions about the timing, manner and justification of the Administration’s decision to engage in hostilities against Iran,” Pelosi said and reiterated her call for a full briefing for lawmakers.

Pelosi said the Trump administration’s “provocative, escalatory and disproportionate military engagement continues to put servicemembers, diplomats and citizens of America and our allies in danger.” She called on the administration “for an immediate, comprehensive briefing of the full Congress on military engagement related to Iran and next steps under consideration.”