In a demoralizing blow to Iraq's offensive against Islamic State, a suicide bomber from the militant group managed to kill two Iraqi army generals in a single strike on Thursday, according to military accounts.
The attack -- which also killed three other soldiers and injured 10 others, according to a military statement read on state television -- took place on the front lines north of Ramadi, the capital of Anbar province in western Iraq. Islamic State fighters seized Ramadi in mid-May after a protracted struggle.
The Sunni Muslim extremist group has captured about one-third of Iraqi territory, extending the "caliphate" it had already declared in parts of Syria. Iraq's U.S.-trained army, plagued by disorganization and desertion, has struggled to regain towns and territory lost to Islamic State, despite a yearlong campaign of U.S.-led airstrikes against the group.
In addition to maintaining a grip on much of Anbar province, Islamic State fighters are seeking to seize the initiative elsewhere in Iraq, renewing a siege of Beiji, an important oil-refining center north of Baghdad.
Backed by allied tribesmen, the army has been moving toward Ramadi, which it is trying to wrest from Islamic State, together with Fallouja, another principal city in the province. The military said a suicide attacker drove a single bomb-laden vehicle into advancing forces.
"An explosive vehicle approached us, and we dealt with it, but the resulting explosion led to the deaths of the two army leaders," said Brig. Gen. Yehia Rasoul, a Defense Ministry spokesman.
In its claim of responsibility, Islamic State said four explosives-rigged vehicles and six fighters were involved in the attack, and that one of the bombers was a German national. Its account could not be independently verified, but the group has many Western nationals among its ranks.
Iraqi military officials vowed the offensive would continue despite the high-level loss of life.
"We will not stop. ... We will continue to push ahead," Defense Ministry spokesman Brig. Gen. Yahya Zubeidi declared on state TV, according to the Associated Press.
The slain senior commanders were identified as Brig. Gens. Abdel Rahman Abu Regheef and Safeen Abd Majeed. In keeping with Islamic practice, the two were buried the same day, with senior government officials in attendance at the funeral in Baghdad.
Meanwhile, another Islamic State suicide attacker struck in neighboring Syria, a monitoring group reported. The Britain-based Syrian Observatory for Human Rights said the bombing occurred outside the town of Marea, near the Turkish frontier. Islamic State fighters have already seized five villages in the area, activists said.
The U.S.-led military coalition, with new cooperation from Turkey, is seeking to create a buffer zone along the Syria-Turkish border free of Islamic State fighters. But the group has moved aggressively to seize territory in northern Aleppo province, near the envisaged safe zone.
Infighting among rebel groups with little in common but a desire to topple Syrian President Bashar Assad is also complicating the effort, as is Turkey's campaign of airstrikes against Kurdish fighters in Turkey and northern Iraq. Kurdish forces have proven the most reliable ally in the ground fight against Islamic State.
Special correspondent Amro Hassan contributed to this report.