Kurdish and Iraqi forces fought to hold back advancing jihadists on the Syria-Turkey border and near Baghdad on Wednesday as Washington pushed to rally its allies against the Islamic State group.
In the Syrian town of Kobane on the Turkish border, Kurdish fighters backed by a flurry of US-led air strikes were reported to have stopped IS fighters from gaining more ground and had even recaptured some positions.
US Central Command said American aircraft struck the jihadists with 18 raids near Kobane on Tuesday and Wednesday, hitting 16 buildings occupied by the group.
In Iraq, pro-government forces beat back an hours-long jihadist attack on a key city west of Baghdad, while reinforcements reached a strategic town threatened by militants.
But US military officials warned on Tuesday that IS had the "tactical momentum" and President Barack Obama was to hold a video conference with the leaders of Britain, France, Germany and Italy to discuss the IS threat.
Obama told military chiefs from more than 20 allies on Tuesday they are facing a "long-term campaign" against IS.
"There are not quick fixes involved. We're still at the early stages," Obama said after the talks in Washington.
"As with any military effort, there will be days of progress and there are going to be periods of setback," he added.
Obama's call with European leaders was to start at 1500 GMT and last about an hour, with the Ebola epidemic and peace efforts in Ukraine also on the agenda.
Obama has expressed special concern for Kobane, which has become a symbolic battleground in the fight against IS, and about halting the IS advance in Iraq's western Anbar province.
Fresh US-led strikes could be seen hitting IS positions in Kobane on Wednesday, an AFP reporter across the border in Turkey said.
- Clashes for Kobane HQ -
A monitoring group said fighting was concentrated on the former Kurdish military headquarters in northern Kobane which IS seized on Friday.
The Britain-based Syrian Observatory for Human Rights said Kurdish forces had retaken two IS positions near the headquarters and pushed the jihadists from several streets to its west, but IS fighters appeared to remain in control of about half the town.
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Turkey, a NATO member, has stationed troops, tanks and artillery along the border -- in some cases only a few hundred yards from the fighting -- but has not intervened.
It also has yet to allow US jets to mount attacks from its territory and complicated issues Tuesday by bombing Kurdish rebel targets in the southeast of the country.
In Iraq, security personnel and tribesmen repelled a seven-hour assault on the city of Ramadi, the capital of the embattled Anbar province.
IS jihadists attacked from three directions after hitting the city with mortar fire, police Captain Tahsin al-Dulaimi said.
The town of Amriyat al-Fallujah, a key area closer to the capital that is one of the last parts of Anbar still holding out against the jihadists, also received reinforcements from the Iraqi army on Wednesday.
Local forces warned on Tuesday the town was in serious danger, with its police chief saying that if Amriyat falls "the battle will move to the gates of Baghdad" and the holy Shiite city of Karbala.
- Rising support for US troops -
Its fall would increase the danger to Baghdad, but IS fighters would still have to capture a significant stretch of government-controlled territory before reaching the capital.
Government forces have suffered a string of bruising setbacks in Anbar in recent weeks, prompting some officials to warn that the entire province, which borders Jordan, Saudi Arabia and Baghdad province, could fall within days.
Some officials in Anbar have argued anything short of an intervention by US ground forces would lead to Anbar falling into jihadist hands.
Washington has ruled out sending troops back to Iraq to fight IS, but a poll published Wednesday showed a rising number of Americans think US ground forces are needed.
Forty-one percent of those surveyed believe the fight should include both air strikes and ground troops, up from 34 percent in September, according to the NBC News-Wall Street Journal poll.
IS has seized control of large parts of Syria and Iraq, declaring a "caliphate" in June and imposing its harsh interpretation of Islamic sharia law.
The group has committed widespread atrocities, including attacks on civilians, mass executions, torture and forcing women and children into slavery -- a practice US Secretary of State John Kerry denounced on Tuesday as "abhorrent".