The U.S., along with Arab allies, carried out a series of attacks Tuesday on the Islamic State in Syria. Video posted to social media purports to show the aftermath of those airstrikes. (The Washington Post)

The start of U.S.-led airstrikes in Syria drew mixed reactions across the Middle East and around the world Tuesday, ranging from staunch support by Britain to harsh condemnation by Russia.

In the Middle East, the fight against Islamic State militants is shifting regional dynamics, winning support from Arab nations that opposed previous U.S. military inventions in the region. At least on the first day of bombing, there was little public backlash, with virtually no outcry beyond a pro-Islamic State protest in Istanbul.

Egypt, the most populous Arab country, is prepared to back the war against the militants, a Foreign Ministry spokesman said, noting the Egyptian government’s fight against terrorists and political Islam.

Bahrain, Jordan, Saudi Arabia and the United Arab Emirates all issued statements acknowledging participation in the airstrikes, though none even mentioned the U.S. involvement. Qatar, the other Arab partner in the airstrikes, said nothing.

The attacks against the Islamic State militants were openly welcomed by rebels who have fought for three years against the government of President Bashar al-

Before getting on a flight Tuesday to New York City, where he was expected to speak about climate change, President Obama addressed the airstrikes that the U.S. launched Monday night against the Islamic State in Syria. (AP)

“We are glad today to see the international community joining our fight against ISIL and extremism,” said Syrian Opposition Coalition President Hadi al-Bahra, using one of the acronyms for the Islamic State.

Bahra said the airstrikes are a sad necessity that can help head off further militant assaults such as the ones that have forced tens of thousands of civilians from their homes.

The moderate Syrian rebel forces that answer to his U.S.-backed opposition movement can fill the vacuum left by airstrikes against militants, Bahra said. But he said the longtime U.S. refusal to provide rebels with antiaircraft and other heavy weaponry is hampering the effort.

“We did hold on, and we had some successes,” Bahra said. “But really, we cannot stand for long if we are not being assisted.”

The reaction from Damascus was somewhat opaque. The Syrian Foreign Ministry simply noted that before the bombing started, Washington had notified Damascus through its envoy to the United Nations. U.S. officials countered that they had provided only a general warning about the possibility of military action and had not coordinated with Assad’s government.

If Damascus was subdued, some of the government’s most prominent backers bluntly characterized the airstrikes as immoral and unlawful.

In Moscow, where President Vladimir Putin has been an important ally to Assad, the Foreign Ministry called the airstrikes a violation of international law — and furthermore, it added, doomed to fail.

“Attempts to achieve one’s own geopolitical goals in violation of the sovereignty of countries in the region only exacerbate tensions and further destabilize the situation,” a Russian Foreign Ministry statement said.

More condemnation came from Lebanon, where Hezbollah is another ally of the Assad regime and has thousands of Shiite Lebanese militiamen fighting beside Syrian troops against the Sunni fighters from the Islamic State.

“Everyone knows that Hezbollah is against ISIS,” said Hezbollah leader Hasan Nasrallah, using another acronym for the group. “We fight them and sacrifice and confront them.”

But, he added, “America is not in a moral position that allows them to fight terrorism.”

In Europe, one of the most straightforward voices of support came from Britain, which is not yet participating in the air campaign. “The prime minister supports the latest airstrikes against ISIL terrorists which have been carried out by the U.S. and five other countries from the gulf and Middle East,” a Downing Street spokesman said.

In the United States, several Muslim and Arab groups expressed concern that a military campaign won’t eradicate violent extremism. Several faulted Washington as failing to provide support earlier to rebels fighting the Syrian government, allowing Islamist militants to flourish.

“By not supporting the mainstream Syrian opposition, it created a vacuum that ISIS entered,” said Ibrahim Hooper, a spokesman for the Council on American-Islamic Relations. “Unless there’s increased support for the mainstream opposition and support for Syrian people seeking freedom, we merely become an extension of Assad’s air force.”

Salam Al-Marayati, head of the Muslim Public Affairs Council, said the airstrikes, while necessary to confront the immediate threat posed by Islamic State militants, are not a long-term solution.

“I believe U.S. policy remains shortsighted,” he said. “It only manages the symptoms of violent extremism. It doesn’t deal with the root causes. Unfortunately, I see the problem of violent extremism remaining in the region for a time, beyond even this current threat of ISIL.”

Gearan reported from New York. Rebecca Collard in Beirut contributed to this report.