The Kamajor militia, which has done most of the recent fighting against the rebels, and includes many child recruits in its ranks, is finding co-operation difficult.
He said the rescue operation was "difficult because huge amounts of rocks have to be removed".
Judging by the past, close co-operation may prove difficult.
We are still trying to restore the mechanics of the geopolitical system to smooth operation in the most difficult conditions.
The complexity of Afghanistan's society and the imminent onset of winter and Ramadan will combine to make it the most difficult military operation in his career, he predicted.
As I regained my health, I had a lot of time to think about what we always hear about surgery but very rarely actually experience: The recovery from any medical procedure is more difficult than the operation itself.
The Tea Party is a diffuse operation, and it can be difficult to pin down its stand on any given issue.
"We are grateful for the patients' and public's understanding and co-operation during what can be a difficult and stressful situation, " she added.
The change in military strategy was described by British officials as a "difficult and high risk" operation.
By revealing authorship the intelligence authorities have just made it more difficult to do the next intelligence operation.
It found operating in Hong Kong so difficult that it moved its entire operation to Silicon Alley in New York this month.
By the standards set by the group, it would be difficult to classify the so called Operation Invade Wall Street as anything but a disappointment.
So it was very difficult to have a founder running a big operation.
On Saturday Mr Hollande said it would be wrong to assume the operation was over while Mr Traore said it would be difficult to completely rid the country of Islamists.
So in essence we have our own local manufacturing and distribution operation that, in some cases, they would have a difficult time matching.
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Mr Cameron had earlier admitted in a speech at Moscow State University that there remained "difficult issues that hamper mutual trust and co-operation" between the UK and Russia.
He says it was clearly a carefully planned operation and the crew were pleased to have come through the most difficult stage of the voyage without incident.
But it signals an early end to bipartisanship and bodes ill for the future of more difficult legislation, which will require a lot more co-operation.
Strong winds and high seas made search conditions difficult and by Thursday afternoon Dutch coastguard spokesman Peter Westenberg said the operation had stopped.
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Freeport, which is handling the rescue operation, said in a statement on Tuesday that "the rescue process is difficult and will take some time to complete".
Much of the fighting in the operation is at elevations above 11, 000 feet, where thin air makes breathing more difficult.
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