Huawei ban fans China-U.S. worries, hits FTSE 100; Thomas Cook slumps

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* FTSE 100 down 0.3%

* FTSE 250 up 0.3%

* Thomas Cook slumps to multi-yr low

* Burberry down after FY report

* Sophos surges on better-than-expected profit

May 16 (Reuters) - Britain's FTSE 100 retreated on Thursday as U.S. curbs on telecom group Huawei further strained relations between Beijing and Washington, while travel group Thomas Cook dipped to a 6-1/2-year low on another profit warning.

The main index edged 0.3% lower by 0716 GMT, while strong earnings reports helped the midcaps climb 0.3% higher.

Despite reports that differences with Beijing as well as Europe may dissipate, U.S. President Donald Trump upped the ante with China once again, signing an executive order on telecoms citing national security and effectively blacklisting Huawei .

Asia-focused stocks including HSBC and Prudential reeled in response.

Luxury brand Burberry, whose shares have recently been hit due to Sino-U.S. trade tensions, gave up 3.2% after reporting broadly flat full-year results.

Thomas Cook, the world's oldest travel firm, slumped 13% to levels not seen since November 2012 after saying economic and political uncertainty would affect profits this summer.

Larger rival TUI fell 1.2% following Thomas Cook's profit alert.

On the FTSE 250, cyber security firm Sophos surged 16%, tracking its best day in over a year, after reporting key metrics above market expectations. (Reporting by Muvija M and Shashwat Awasthi in Bengaluru; Editing by Angus MacSwan)