On Wednesday night, President Barack Obama announced plans for increased U.S. airstrikes in Iraq and a new military offensive in Syria to destroy the Islamic State -- a message aimed not only at Americans, who were listening on the eve of the anniversary of the 9/11 attacks, but also at the inhabitants of the regions where the group also known as ISIS has found a haven. “In a region that has known so much bloodshed, these terrorists are unique in their brutality," Obama said. "If unchecked, these terrorists could pose a growing threat beyond that region.”  

Syria and Iraq, the two countries where ISIS currently holds territory, had opposite reactions to the U.S. plans. President Bashar Assad's government in Syria has said that while ISIS must be destroyed, any U.S. airstrike on its soil should first be approved by Damascus. Iraq, on the other hand, welcomed the strikes.

“What’s happening in Syria is coming across to Iraq. We cannot cross that border. It’s an international border, but there is a role for the international community, for the United Nations to do that role,” Iraqi Prime Minister Haider al-Abadi said Wednesday.

Other regional leaders also weighed in.

In Lebanon, Foreign Minister Gebran Bassil called for “total war” against ISIS, but emphasized that the Arab world would need to come together to fight the militant group. “The response is a joint Arab war against this organization,” Bassil said. But not every country in the region is ready to join the coalition, and no leader has made any explicit promises about fighting ISIS.

Turkey -- the only Middle East country that is a member of NATO -- is also one of the staunchest opponents of joining the fight in Syria against ISIS. Turkish media reported officials as saying the country would be less likely to join Obama’s coalition because of its hostage situation. ISIS is currently thought to be holding 49 Turkish nationals, including diplomats and children. At the same time, the Turks are hosting thousands of refugees displaced from the Syrian civil war and providing humanitarian aid.

Haaretz, the Israeli newspaper, reported Thursday that Prime Minister Benjamin Netanyahu warned the West against strengthening Iran in its fight against ISIS.

"Iran is seeking to keep the enriched nuclear material and one day kick out the inspectors and break out for a nuclear weapon," the prime minister said. Netanyahu also said Israel was “doing its part” in the fight against ISIS, but did not provide more detail. But on Wednesday, Israeli Justice Minister Tzipi Livini told Haaretz that “strong legislation and harsh words against ISIS are good, but not enough.”

U.S. Secretary of State John Kerry is currently in Saudi Arabia, where he is meeting with Arab leaders to coordinate strategy against ISIS. The meetings, hosted by the Saudis, include the United Arab Emirates, Qatar, Kuwait, Bahrain, Oman, Egypt, Jordan, Turkey, Lebanon and Iraq. 

Saudi Arabia has agreed to provide bases for the training of Syria's "moderate" rebels. (The U.S. is already training a few hundred in Jordan.) The government released a statement Thursday about its commitment to the U.S. in fighting the Sunni militant group.

"The Kingdom of Saudi Arabia wishes to see the defeat and destruction of all al Qaeda networks and the Islamic State of Iraq and Al Sham (ISIS) operating in Iraq. Saudi Arabia does not provide either moral or financial support to ISIS or any terrorist networks. Any suggestion to the contrary is a malicious falsehood," the statement said. Kerry is expected to meet with King Abdullah Thursday evening.

Qatar is the wild card. Obama and Kerry need to bring Doha into the coalition. The tiny Gulf state, which casts an outsized shadow in the region with its wealth and media reach, has been implicated in providing funds and weapons to ISIS. According to a report by the New York Times, "The state itself has provided at least some form of assistance -- whether sanctuary, media, money or weapons — to the Taliban of Afghanistan, Hamas of Gaza, rebels from Syria, militias in Libya and allies of the Muslim Brotherhood across the region."

Obama said in his speech that he had a strategy to combat ISIS. But Thursday's meeting in Saudi Arabia and split reactions from some in the Middle East complicate his efforts to gather enough reliable partners to make a difference.