WASHINGTON – The United Kingdom flew a squadron of fighter jets over Iraq on Saturday, soon after its Parliament voted overwhelmingly to use air power on Islamic State assets below.The vote added the significant air power of the Royal Air Force to a burgeoning list of countries prepared to attack the terrorist network in Iraq specifically, where it still holds valuable, populated territory. Their mission comes at the expressed invitation of the Iraqi government and without much fear of direct reprisal: Islamic State cannot reach British Tornados, or their American, French, or Australian partners flying with them.Britain’s first mission was intelligence-gathering, the Defense Ministry said, but its aircraft were prepared to conduct their first strikes. Tornados have sophisticated surveillance and precision-guidance capabilities, the ministry noted.Denmark and Belgium also agreed to join the air campaign over the weekend.The United States has been conducting air strikes over Iraq since August 8 and over Syria since last Tuesday as part of a campaign to “degrade and destroy” the Islamic State insurgents who have captured swathes of both countries, beheaded Western hostages and ordered Shi’ites and non-Muslims to convert or die.With Friday’s parliamentary vote, Britain joined a US-led coalition supported by some Gulf and European nations against the rebel group.France has also conducted air strikes in Iraq, while Washington said Saudi Arabia, Jordan and the United Arab Emirates joined strikes over Syria on Saturday.French fighter jets struck Islamic State targets in Iraq on Thursday, a prompt answer to the beheading of a French tourist Herve Gourdel in Algeria by Islamic State supporters, who said the killing was punishment for Paris’s decision to become the first European country to join the US-led bombing campaign.No European nation, however, has joined the US in its “borderless” air war on Islamic State in Syria. Fighting has flared between Islamic State and the Kurds living near Syria’s border with Turkey, dragging Turkey, a NATO ally, deeper into the conflict.Several eyewitnesses reported fresh strikes from the US-led coalition over Syria, which includes the air power of five Sunni Arab nations.One independent monitoring group claimed 31 bombings took place nearby Raqqa, the self-declared capital of Islamic State.US Central Command did confirm US-led strikes on Islamic State assets near Kobani, however, a border town under siege for over a week.Those air strikes did not appear to deter the group.Shelling continued throughout the day, and some projectiles from the fight also hit Turkish territory on Saturday, contributing to fears of military spillover compounding a humanitarian crisis. An estimated 170,000 Syrian Kurds have fled over the border in the last month.Turkey’s President Recep Tayyip Erdogan pushed back against criticism from regional press that his government, directly affected by the crisis and in direct talks with Islamic State, has not contributed adequate force to the coalition against the group, which includes more than 40 nations.“You can’t finish off such a terrorist organization only with air strikes,” Erdogan said in an interview with the Hurriyet newspaper. “Ground forces are complementary...if there’s no ground force, it would not be permanent.”“No one is responsible for protecting your borders,” he continued. “We are the ones who will protect our own borders.”Asked whether Turkey was considering the establishment of a secure zone in Syria along its border, Erdogan said that should be done alongside regional partners.“We need to have legitimacy within the international community,” he said. “This is not only about Turkey, but about the 1.5 million people returning to their own land.”The Pentagon has said on numerous occasions that US President Barack Obama’s strategy does not suggest air power alone can successfully take back eastern Syria and northern Iraq from Islamic State.The strategy relies on air power, but primarily on Iraqi troops fighting and holding territory they have lost in their own country – and the training and equipping of a Syrian force to do the same in their own.General Martin Dempsey, chairman of the Joint Chiefs of Staff, said on Friday that 12,000 to 15,000 well-trained Syrian troops would be required to regain territory.That will take months, if not years, the Pentagon says, likely taking this mission beyond the current presidency.Reuters contributed to this report.