MURSITPINAR, Turkey — New allegations have emerged that Islamic State extremists have expanded their arsenal with chlorine bombs and captured fighter jets — weapons that could help the militants in Iraq and Syria.
Kurdish fighters in the key Syrian border town of Kobani have held off a month-long offensive by the Islamic State group with the help of a U.S.-led campaign of airstrikes.
Turkey's president said he will allow Syrian rebels to transit through his country to help the town's beleaguered defenders, but both the Kurds and the rebels denied any such plan was in the works, underscoring differences over strategy that are hindering efforts to roll back the extremists.
In Iraq, officials said Islamic State militants used chlorine gas during fighting with security forces and Shiite militiamen last month north of Baghdad. If the reports are confirmed, it would be the first time the Sunni extremists tried to use chlorine since their seizure of large parts of Syria and northern Iraq earlier this year.
The statements in Iraq came two days after Kurdish officials and doctors said they believed IS militants had released some kind of toxic gas in an eastern district of Kobani. Aysa Abdullah, a senior Kurdish official based in the town, mentioned the attack took place late Tuesday and that some people suffered symptoms that included dizziness and watery eyes. She and other officials said doctors lacked the equipment to establish what kinds of chemicals were used.
U.S. Secretary of John Kerry said he could not confirm the Iraqi allegations that toxic gas was used against security forces and Shiite militias, but he called the charges "extremely serious." He said chlorine can be considered a chemical weapon if it is mixed with other toxic agents.
"The use of any chemical weapon is an abhorrent act," Kerry said at a news conference in Washington. "It's against international law. And these recent allegations underscore the importance of the work that we are currently engaged in."
Three Iraqi officials — a senior security official, a local official from Duluiya and an official from Balad — told The Associated Press that the Islamic State group used bombs with chlorine-filled cylinders during clashes in late September in the two towns.
The militants have failed to capture both Duluiya, 75 kilometers (45 miles) north of Baghdad, and Balad, 80 kilometers (50 miles) north of the Iraqi capital.
In the attacks, about 40 troops and Shiite militiamen were slightly affected by the chlorine and showed symptoms consistent with chlorine poisoning, such as difficulty in breathing and coughing, the three officials said. The troops were treated at a hospital and recovered quickly.
The senior security official said it was most likely that the Islamic State fighters used chlorine from water purification plants located in the areas they had overrun.
Earlier this year, a U.N. fact-finding mission sent to investigate alleged chlorine attacks in Syria was ambushed and briefly detained by armed men in rebel-held territory. The mission had said it was virtually certain chlorine had been used as a chemical weapon in northern Syria.
Syrian President Bashar al-Assad had agreed with the United States and Russia to dispose of his chemical weapons — an arsenal that Damascus had never previously formally acknowledged — after hundreds of people were killed in a sarin gas attack on the outskirts of the capital in the summer of 2013. Chlorine was not listed as part of the Syrian arsenal.
Last week, the Britain-based Syrian Observatory for Human Rights reported that IS militants flew three MiG fighter jets with the help of former Iraqi air force pilots who were now members of the extremist group. The report could not be independently confirmed, and U.S. officials said they had no reports of the militants flying jets.
The group is known to have seized warplanes from at least one air base captured from the Syrian army in Raqqa province earlier this year. Militant websites had posted photos of IS fighters with the warplanes, but it was unclear if they were operational.
Syrian Information Minister Omran al-Zoubi said this week that Syrian aircraft bombed two of the three jets on the runway as they landed at Jarrah air base in northern Syria.
Meanwhile, Turkish President Recep Tayyip Erdogan said Friday that Ankara would allow hundreds of Syrian rebels to travel to Kobani to help Kurdish fighters there battling IS militants.
The announcement by Erdogan, made on a visit to Estonia, suggested more assistance for Syrian Kurdish fighters since mid-September, when the IS group launched an offensive to try to take Kobani. Militant positions around the town are under bombardment by airstrikes from the U.S.-led coalition.
Erdogan, a fierce opponent of Assad, said the Western-backed Free Syrian Army would send 1,300 fighters to Kobani. He told reporters that the rebels were negotiating their route with the Kurdish Democratic Union Party, or PYD, which governs Kobani.
Syrian opposition activists denied there were any such plans, and Kurdish fighters reacted angrily to the announcement, viewing it as a slight to their dogged defense of the town over the past month.
Syria's Kurds are seen as the most successful group fighting the IS militants on the ground. They are being aided by the U.S. airstrikes, and have received air-dropped shipments of weapons.
The Syrian Kurds accuse Turkey of trying to undermine their efforts. Earlier this week, Turkey announced that Iraqi Kurds, who have better relations with Ankara, would enter Kobani through its territory.
The Turkish government is reluctant to aid the Syrian Kurdish forces because it views them as an extension of the Kurdistan Workers' Party, which has waged a long insurgency in Turkey and is designated a terrorist group by the U.S. and NATO.
"We need weapons, we are not in need of fighters," said Nawaf Khalil of the PYD.
"There has been no communication with us," Khalil said of Erdogan's announcement.
A spokesman for the Western-backed Syrian opposition in exile, Kenan Mohammed, also said there were no plans to send fighters to Kobani. He and another spokesman said Syrian rebels were already badly overstretched trying to defend opposition-held areas, particularly in the countryside around Aleppo, from advancing government forces.
Hadid reported from Beirut. Associated Press writer Jari Tanner in Tallinn, Estonia, Lara Jakes in Washington and Sameer N. Yacoub and Qassim Abdul-Zahra in Baghdad contributed to this report.