This failure has exacerbated concerns that the UK could be "trapped" in the backstop.
Now, Mr Shekau appears to have undermined the government's claims: "You said it was an ordinary fire, but it was me in that fire," he said in his video.In laying claim to the bombing, Boko Haram has exacerbated concerns over its ability to reach deep into the south of the country.
A leak sprung in a temporary coffer on November 18, which Michelin explained has exacerbated concerns about the stability of the dam.
Massive budget cuts to public education have exacerbated concerns about the quality of teaching and sinking student aptitude in math and science.
Western sanctions against wealthy Russians imposed during the Ukraine crisis have hit demand for luxury goods, and mass democracy protests in Hong Kong, which closed off shopping districts, have exacerbated concerns about a slowdown in China, where the government has been cracking down on corrupt gift giving.
A four-page summary of Mueller's findings, which Barr delivered to Congress on Sunday, has exacerbated Democrats' concerns.
In one case, the small-business owner's existing lender has exacerbated his concerns by telling him that all sorts of bad things will happen if he changes financiers.
The heightened chaos in neighboring Syria has exacerbated the concerns, bringing tens of thousands of refugees into the country, emboldening Islamist dissenters and aggravating existing social, economic and political divides in ways that test long-held assumptions about Jordan's cohesion.
"The current failure of the BSUH specialist neurosurgery service has exacerbated our concerns," she said.
On 4 March 2011, Matt Stoller had headlined "Angelo Mozilo, Tea Partier?" and revealed a 1 September 2004 e-mail from Mozilo to other executives at Countrywide, in which Mozilo had said, "The upcoming election has exacerbated my concerns in that a Kerry win could cause a serious disruption in the economy if he is successful in rolling back a substantial portion of the tax breaks initiated by Bush.
Earlier this year, the United States underwent the longest period in history without a single tornado death, which has exacerbated human overpopulation concerns.
