(CNN) Secretary of State Rex Tillerson says the United States is waiting to see how widespread arrests in Saudi Arabia play out in the coming weeks, but he is so-far inclined to believe the Saudi account that they are an effort to fight corruption.

Tillerson said he is basing that assessment on his conversation with Saudi Foreign Minister Adel bin Ahmed al-Jubeir Tuesday.

"I think based on that conversation, it's well-intended," Tillerson told a pool reporter aboard his plane early Friday. "How disruptive it's going to be remains to be seen."

"How they choose to deal with it at this point is still a bit unclear," he acknowledged, "but I wouldn't want to read more than what we know at this point and what the foreign minister shared with me."

Tillerson, who is currently accompanying President Donald Trump on his trip to Asia, said he was also assured by Jubeir that Lebanese Prime Minister Saad Hariri is not being held in Saudi Arabia against his will, as the Lebanese government is alleging.

"I was assured by the foreign minister that this was a decision that Prime Minister Hariri took on his own," said Tillerson.

Officials in Lebanon have claimed in recent days that Saudi Arabia is restricting Hariri's movements since he arrived in the country after going on television nearly a week ago to say he was resigning.

State Department Spokeswoman Heather Nauert said the top US diplomat in Saudi Arabia, Chargé D'Affaires Christopher Henzel, was able to meet with Hariri Wednesday, but she could not say where the meeting took place.

"In terms of the conditions of him being 'held,' or the conversations between Saudi Arabia and Prime Minister Hariri, I would have to refer you to the government of Saudi Arabia," she said, "and also to Mr. Hariri's office."

Hariri's departure has threatened the fragile coalition government in Lebanon, and raised concerns about the potential for conflict with neighboring countries, including Saudi Arabia.

Tillerson acknowledged those concerns Friday, and urged calm.

"The United States supports the stability of Lebanon and is opposed to any actions that could threaten that stability," Tillerson affirmed in a written statement. "There is no legitimate place or role in Lebanon for any foreign forces, militias or armed elements other than the legitimate security forces of the Lebanese state -- which must be recognized as the sole authority for security in Lebanon."

"The United States cautions against any party, within or outside Lebanon, using Lebanon as a venue for proxy conflicts or in any manner contributing to instability in that country," the statement continued.

Several State Department officials tell CNN Hariri's resignation caught the Trump administration by surprise, and expressed concern it may have been forced by Saudi Arabia, where Hariri also holds citizenship.

These officials said Tillerson's statement was meant to send a tough message to Iran, but also to Saudi Arabia's government, which may have sought to remove Hariri out of concern he had become too accommodating to Iran, Saudi Arabia's main rival in the region. Hariri is part of a coalition government with Iranian-backed Hezbollah.

Both Saudi Arabia and Israel have been pressuring the United States for months to crack down further on Iran and Hezbollah, several current and former administration officials tell CNN.

Last month, the Trump administration launched a new offensive against Hezbollah, claiming the group aspires to conduct attacks against the US homeland. Several State Department officials said that the agency was pressured by the White House to turn up the heat on the group, which the United States considers a terrorist organization, but is also a powerful political bloc in Lebanon.

Tensions in the region have been further inflamed by a thwarted missile attack targeting Saudi Arabia's capital last week, which originated in war-torn Yemen.

Saudi Arabia has been engaged in the conflict on behalf of exiled Yemeni President Abdu Rabu Mansour Hadi, who was ousted from the capital by Iranian-backed Houthi rebels.

The Saudi government has blamed Iran for last week's missile launch, which the Saudi Crown Prince, Mohammed bin Salman bin Abdulaziz, said "may be considered an act of war against the kingdom."

Tillerson said the United States has not yet determined whether the missile was of Iranian origin, as Saudi Arabia alleges. Later Friday, Lt. Gen. Jeffrey Harrigian, the Commander of US Air Forces Central Command, said the missile appeared to be Iranian-made: "Well how they got it there is probably something that will continue to be investigated over time, but what has been demonstrated and shown based on the findings of that missile that it had Iranian markings on it. That in itself provides us some evidence where it came from."

"We've said for a long time that we are concerned about Iranian support for the Houthi rebels and we do know they're supporting them with weapons," Tillerson noted. "Whether this specific missile came from Iran, it seems very likely but I think we'd like to get the final forensics on it."