Pakistan summoned a senior US diplomat here and lodged a strong protest over America’s alleged "interference" in its internal affairs, according to media reports on Friday. The US State Department on Thursday firmly rejected embattled Prime Minister Imran Khan’s remarks over Washington’s role in an alleged “foreign conspiracy” to oust him from power. In a live address to the nation, 69-year-old Khan discussed a 'threat letter' and termed it as part of a foreign conspiracy to remove him as he was not acceptable for following an independent foreign policy. He named the US as the country behind the threat letter in what appeared to be a slip of tongue. Dunya News quoted sources as saying that the US diplomat was summoned by the Foreign Office (FO) over a “threatening letter” that warned of dire consequences if the Opposition’s no-confidence motion against Khan failed. The step was taken after a decision by Pakistan's National Security Council (NSC) on Thursday. The Foreign Office also handed over a letter of protest to the US diplomat over the language used by a foreign official during a formal communication.