Washington, Aug 6 : The US State Department has said that PTI chief Imran Khan's arrest was Pakistan's internal matter. "Cases against Imran Khan and other politicians on Pakistan are an internal matter," US State Department's spokesperson was quoted by Dawn as saying. The spokesperson added: 'We call for the respect of democratic principles and the rule of law in Pakistan, as we do around the world.' The former Pakistan Prime Minister was arrested in connection with the Toshakhana case. However, independent observers are of the opinion that it would worsen the political crisis. Taking to Twitter, Michael Kugelman, a scholar of South Asian affairs at the Wilson Centre in Washington, posted: 'Not long ago, Pakistan's political crisis appeared to be easing a bit, with the government pledging to step down and make way for a caretaker to prepare for elections.' Member of National Assembly of Paksitan, Mohsin Dawar, who is in North America, posted: 'One PM was convicted on an iqama and now another on selling a wristwatch. Politicians get discredited over such trivial matters while (others) get away' with more serious charges. 'Politicians keep getting used and then are discarded like Imran Khan. We keep going round and round in circles,' he wrote. Several supporters of Khan gathered outside the Pakistan High Commission in London to protest his arrest and chanted slogans in his favour. /IANS