The Trump administration suspects an Iranian missile caused the deadly crash of a Ukrainian passenger jet, Secretary of State Mike Pompeo said at a news conference Friday, confirming earlier intelligence reports.

Meanwhile, Ukraine has gained access to the "black box" from the plane, which records data from the flight and voices from the cockpit. In a WhatsApp message sent to USA TODAY, a spokeswoman for Ukraine's president, Iulia Mendel, wrote: "Yes, Ukraine has access to the black boxes."

Iran's official IRNA news agency reported that the black box would be opened Friday, although it said the process of downloading the information could take up to two months.

If Iran is found to have shot down the plane once the investigation is complete, the U.S. "and the world will take appropriate actions in response," Pompeo said.

"We do believe that it is likely that that plane was shot down by an Iranian missile. We’re going to let that investigation play out," Pompeo said.

The treasury department will issue waivers for anyone who can help facilitate the investigation, Treasury Secretary Steve Mnuchin said. He also announced an array of new sanctions on Iran, including sanctions on eight senior administration officials.

NATO Secretary General Jens Stoltenberg told reporters Friday that he has "no reason not to believe reports" that the plane "may have been downed" by an Iranian missile.

Iran on Friday urged American and Canadian investigators to share any information they have on the crash while again rejecting any suggestion it was brought down by one of its own missiles.

"What is obvious for us, and what we can say with certainty, is that no missile hit the plane," Ali Abedzadeh, head of Iran’s national aviation department, told a press conference in Tehran. "If they are really sure, they should come and show their findings to the world" in accordance with international standards, he added.

Abedzadeh's comments came as Ukraine’s Foreign Minister Vadym Prystaiko tweeted that he and President Volodymyr Zelensky met with U.S. Embassy officials and obtained "important data" about the crash. Prystaiko didn't specify what kind of data it was.

One of Iran's most senior diplomats in Europe meanwhile disputed a suggestion from a journalist that the Ukraine International Airlines crash site outside Tehran had "no security," "was not cordoned off" and that there was "no sign of any investigators."

Hamid Baeidinejad, Iran's ambassador to the United Kingdom, told USA TODAY after a briefing with reporters here that it wasn't true, as CBS News' senior foreign correspondent Elizabeth Palmer tweeted that the crash site was not being protected for investigators and that local "scavengers (were) now picking the site clean."

The allegation is a worrying one in light of the fact U.S intelligence officials believe Iran may have mistakenly shot down the commercial airliner with a missile, which killed all 176 people on board: 82 Iranians, 63 Canadians, 11 Ukrainians, 10 Swedish, four Afghan, three German and three British nationals.

Iran vehemently disputes shooting the plane down and said its initial findings indicated the plane crashed as a result of a technical fault. Palmer, who is in Iran, was able to briefly visit the crash site Friday before being chased away by Iranian officials.

Ukraine's plane crashed just hours after Iran fired ballistic missiles at two U.S. military based in Iraq. That assault came in retaliation for the Pentagon's killing in a drone strike of Gen. Qasem Soleimani, one of Iran's most senior and revered military commanders.

The Trump administration said Soleimani was planning an "imminent" attack against U.S. citizens, but Pompeo on Friday faced several questions about the details of that alleged plot.

"This was gonna happen. And American lives were at risk, and we would have been culpably negligent ... had we not recommended to the president that he take this action against Qasem Soleimani," Pompeo said.

Video has emerged online that appears to show a plane near Tehran being hit with a projectile of some kind, but no conclusive evidence has been released.

Brian Hook, the State Department’s special representative for Iran and a senior policy adviser to Pompeo, said Iran should not do anything to impede the investigation into the crash.

"This needs to be open, transparent and comprehensive," he told reporters during a conference call on Friday.

Baeidinejad said in the briefing that Iran was "fully committed to participating in an international investigation that meets the highest international standards." He also cautioned that the issue "should avoid being politicized" because it was harmful to the friends and family members of those who died in the crash near Tehran's airport.

Tehran and Washington are deeply suspicious of one another after decades of animosity and tensions have increased since the Trump administration pulled out of a nuclear deal between Iran and world powers and reimposed economic sanctions.

Baeidinejad appeared to indicate in the briefing in London that American officials from the National Transportation Safety Bureau, a U.S. government agency, would travel to Iran to participate in the crash investigation. However, there has been no independent confirmation from the NTSB, the U.S. State Department or the White House that such a move would take place.

Late Thursday, NTSB published a statement saying it had received "formal notification" about the crash from Iran's Civil Aviation Organization and would be sending "an accredited representative to the investigation of the crash."

The NTSB followed that up Friday, saying the "designation of an accredited representative is the first step toward that end. No decision has been made about travel and decisions are still being made about how the NTSB’s involvement may unfold."

There has been no indication that this representative would be an American government employee. It would be a major step forward for U.S-Iran government-to-government contact if a U.S. official traveled to Iran. There are very few, if any, known instances of American government employees traveling to Iran since the country's 1979 Islamic Revolution that coincided with protesters in Tehran storming the U.S. Embassy there and holding 52 American diplomats and officials hostage for 444 days.

Contributing: Deirdre Shesgreen, USA TODAY