The US and UK have warned that air strikes alone will not prevent Islamic State (IS) fighters from seizing the Syrian town of Kobane, reports GHN based on BBC.
A Pentagon spokesman said the US and its allies were "doing everything we can from the air" but there were limits to what the campaign could achieve.
Similar views were expressed by British Foreign Secretary Philip Hammond.
A Kurdish leader in Kobane told Reuters news agency IS militants had entered parts of the city amid heavy fighting.
Seizing the town would give IS jihadists full control of a long stretch of the Syrian-Turkish border.
The US also appeared to be at odds with allies over a Turkish idea to create a buffer zone or safe haven along the border.
Three weeks of fighting over Kobane have cost the lives of at least 400 people, and forced more than 160,000 Syrians to flee across the border to Turkey.
"Air strikes alone are not going to save the town of Kobane," Pentagon spokesman Rear Adm John Kirby said. "We know that and we've been saying that over and over again."
He said that ultimately rebel fighters in Syria and Iraqi troops would have to defeat IS militants, but it would take time.
"We don't have a willing, capable, effective partner on the ground inside Syria right now," he said, warning that other towns could also fall to IS.
Likewise, Mr Hammond said that it was "never envisaged" that the use of air power "in this battle would turn the tide in the short-term".
"I don't want to suggest that there is anything readily that the coalition can do that will make a fundamental difference... in the tactical situation that's faced around Kobane," he said.