Activists of the Difa-e-Pakistan Council shout anti-U.S. slogans at a protest in Karachi on Tuesday. Pakistan summoned the U.S. ambassador after President Trump lashed out at Islamabad with threats to cut aid over “lies” about militancy.

A New Year's Day tweet by President Trump has exacerbated tensions in an already fraught relationship. He criticized Pakistan for "lies and deceit" and harboring terrorists