U.S.-led airstrikes against the Islamic State group in Syria have increased tensions among Middle East leaders. The conflict in Syria, which has killed more than 190,000 and displaced close to 5 million people, has already affected the surrounding Middle Eastern countries economically; now it is drawing them in militarily.

The United Arab Emirates, Jordan, Qatar and Saudi Arabia – all Sunni Arab-majority countries --are participating in airstrikes with the U.S. But Shiite-majority parties and countries, including Iran and Hezbollah leaders in Lebanon, publicly oppose the airstrikes against the Sunni extremists of ISIS. 

"These bombings do not have any legal standing, so we can interpret them as an attack," Iranian President Hassan Rouhani told journalists at the United Nations General Assembly Tuesday, adding that Iran also opposed ISIS and focused on “combating extremism.”

"We are against American military intervention and an international coalition in Syria, whether that is against the regime or IS," Hezbollah leader Sayyed Hassan Nasrallah said in a speech aired on Hezbollah's al-Manar television channel. "America, is in our view, the mother of terrorism and the origin of terrorism."

Other regional players, such as Israel and Turkey, have not taken a strong public stance on the airstrikes, though Turkish rhetoric has vacillated between joining the military campaign and avoiding it at all costs.

The Syrian regime has not released a statement on the airstrikes on its territory, but had previously said any intervention would have to first be approved by Damascus. The Syrian foreign minister reported Tuesday that Washington informed Assad's government before launching the airstrikes, and according to Reuters, Iran was also informed.

So far, no Sunni-majority country has come out in opposition of the airstrikes, despite the fact that ISIS is a Sunni militant group. But reaction on the ground in Iraq and Syria — the two countries where the U.S. is bombing — could be quite different.

When ISIS began to take over large parts of northern and western Iraq, Sunnis told the International Business Times that they did not want the U.S. to intervene again. Some, mostly those from Anbar and Fallujah, said that ISIS was a better option than then-Prime Minister Nouri Al-Maliki. Many said they opposed U.S. intervention because the Iraq War had resulted in another oppressive leader.

Sunni rebels, the same people using U.S. weapons in Syria, condemned the airstrikes Tuesday, claiming any foreign intervention in the country against ISIS would strengthen Assad. 

Other members of the opposition in Syria, those fighting under the umbrella of the Free Syrian Army in northern Aleppo province, said Wednesday that they were operating as normal and that the Syrian military was continuing to bombard them. In a series of conversations with the IBTimes, FSA commanders and soldiers said they would rather battle the Assad regime and extremist groups themselves, but need anti-aircraft missiles to have a fighting chance. So far, the U.S. and other allies have been reluctant to send such weapons into the country for fear they would fall into the wrong hands.

The airstrikes are certain to intensify the humanitarian crisis in the region. U.N. aid dollars are stretched thin, and Jordan, Turkey, Lebanon and Iraq are already dealing with a flood of refugees from the civil war. U.S. bombings are likely to increase those challenges, and it's not clear how the international aid community would handle another wave of displaced Syrians.