** Shares of British drug makers AstraZeneca AZN.L and GSK GSK.L fall after U.S. President Donald Trump's tariff warning on pharma sector
** AZN down 1.5% at 10,500p and GSK GSK.L falls 1.3% at 1,461.5p; both among top losers on FTSE 100 index .FTSE which is up 0.15%
** Trump on Tuesday said tariffs to the pharma sector are "coming very soon"
** Michael Field, chief equity strategist at Morningstar, says that with Trump warning of tariffs on pharma, investors are reacting negatively
** "It's already been questioned heavily whether tariffs are constitutional or not and would they go through, but in the meantime, market has taken a prudent approach and dropping valuations of pharmacy stocks"
** Including session's losses, AZN and GSK are up 0.5% and 8.6%, respectively, so far this year