Washington (CNN) Debate over the threat posed by Iran took on a partisan hue after Trump administration officials briefed lawmakers Tuesday, with Democrats charging that the White House is blowing normal threat levels out of proportion and Republicans insisting that deterrence, not war, is the goal.

Secretary of State Michael Pompeo, acting Defense Secretary Patrick Shanahan, and Chairman of the Joint Chiefs of Staff Gen. Joseph Dunford met with House and Senate lawmakers in response to growing frustration on Capitol Hill about the administration's silence as tensions with Iran have spiked.

Republican lawmakers emerged attributing a series of recent incidents to Iran and its proxies, including a drone attack on a Saudi pipeline, damage to four freighters in the Persian Gulf and a rocket fired near the US embassy in Baghdad.

They said these events constitute Iranian escalation and recent US steps -- including moving a Navy strike group and bomber task force near the Persian Gulf -- are meant both to deter Iran and make clear that the US will respond robustly if its personnel are targeted.

'This is about deterrence'

"We do not want the situation to escalate," Shanahan said. "This is about deterrence, not about war, we're not about going to war."

But Democrats said the Iranian response to the appearance of US warships was predictable, particularly after a year of increasing US economic pressure. They said the threat stream was not unusual for that conflict-ridden part of the world and that they're concerned about possible miscalculations in the near term and the lack of an administration strategy in the long term.

"There are clearly threats to US interests in the region, but those threats are predictable," said Sen. Chris Murphy, a Connecticut Democrat who sits on the foreign relations committee. "Multiple administrations, Republican and Democratic administrations, refused to take the steps that the Trump administration has taken because they knew it would result in the Iranians looking at US assets in the region as targets."

Sen. Bernie Sanders, the Vermont independent and presidential candidate, added that "I worry very much that intentionally or unintentionally, we can create a situation in which a war will take place."

The briefings took place as two US officials told CNN that a rocket attack in late April against US forces at Camp Taji in Iraq was attributed to Iranian backed forces and raised concerns about Iran improving its precision targeting abilities, particularly because a drone was observed hovering at the time.

One of the US officials said that increased Iranian readiness continues to be observed on shore and at sea, though there are no indicators of any kind of imminent attack and the moves could be defensive.

Lawmakers from both parties had expressed concerns that they haven't been given information about the nature of Iran's threat, even as administration officials hinted at a potential need for military action.

President Donald Trump contributed to the confusion about the intelligence, splitting from his most senior officials' message about an imminent threat from Iran on Monday. "We have no indication that anything's happened or will happen, but if it does, it will be met obviously with great force," Trump said at the White House.

'Imminent'

Pompeo had warned of escalating and "imminent" attacks by Iran in early May. On Tuesday, Republicans emerging from the briefings said those imminent attacks had been thwarted by the administration's decision to send warships to the region.

An "attack against American personnel has not occurred," said Utah Republican Sen. Mitt Romney. "And perhaps that's related to the fact that we stood up a very strong deterrent message to the people in the leadership in Iran ... that is the purpose of what's happening."

Texas Rep. Michael McCaul, the most senior Republican on the House Foreign Affairs Committee, said, Tthere was an escalation by Iran and its proxies, this is a response to de-escalate and provide a deterrent strategy so that Iran does not become aggressive."

"There's no intention to go to war in the region," McCaul added. "This is a deterrent operation to stop Iran's escalation and aggression in the region."

Iranian officials have repeatedly said they do not want war, but will push back against US aggression.

Sen. Lindsey Graham, a South Carolina Republican, said the administration officials had explained "how the Iranian threat streams were different than in the past."

'That's not news'

The attack on the ships in the Gulf and on the Saudi pipeline were "coordinated and directed by the Iranian government, the ayatollah," Graham said.

He added "that we picked up strong intelligence that they had given the Shiite militia basically more running room and direction. And that attacks against American interests and personnel were imminent."

That was a step father than Pompeo went in an interview with radio host Hugh Hewitt, in which the top US diplomat said "it was quite possible" that Iran was behind the attacks.

Democrats emerging from the briefings echoed Murphy in his assessment that the threat streams weren't that different than they've been in the past.

Rep. John Garamendi, a California Democrat, told CNN's Brooke Baldwin that Pompeo and Shanahan had talked about Iran's support for Hezbollah and other groups. "That's not news," Garamendi said. "It's not new ... there's no need for the carrier force to be there."

Rep. Adam Smith, the Washington Democrat who heads the House Armed Services Committee, told reporters he didn't think military engagement was in the cards, but added that he is also concerned about risks of an accidental clash.

"I don't anticipate the use of military force," Smith told reporters. "I think the President is, I take him at his word that he doesn't want to get into a war. But that doesn't mean that there's not a risk of it. And we need to manage that risk."

Murphy suggested that the administration is setting itself up for a clash by taking steps that it knows will engender an Iranian response and, given that, questioned the White House's longer-term vision for its approach to Iran, describing it as "blind escalation."

"There's no way to defend, rationalize, or explain what the Iranians have done," Murphy said. "Nothing we have done justifies attacks on ships and on oil pipelines. That being said, it's entirely predictable. We knew that by taking these steps, the Iranians would push back. And without an overall strategy for how this set of escalatory actions ultimately leads back to the negotiating table, it doesn't seem like well thought out policy."

"This briefing was all about tactics, not about strategy," Murphy said. "There was no effort to lay out a thoughtful, interdepartmental strategy for how this is ultimately going to wind up in a better deal being signed by the Iranians than was signed by the Obama administration."

'On the brink'

Smith questioned whether the administration's current approach is working and said he didn't get satisfactory answers. "What our maximum pressure campaign has done in terms of achieving our objectives, I have not seen," Smith said. "It was not very enlightening from what they said in there in terms of how it's going to progress ... how our actions are going to force the changes we're looking for."

The Connecticut lawmaker made an appeal for diplomacy.

"Right now we're on the brink of conflict, and they need to have a way to deconflict with the Iranian government," Murphy said. "So in the short term, I think they, the two governments need to start talking to each other."

"I don't know why this administration can talk to the North Koreans, but can't talk to the Iranians. Especially right now when we could be on the verge of something pretty cataclysmic," Murphy said.