By Humeyra Pamuk and Katharine Jackson WASHINGTON, June 29 (Reuters) - The United States said a high-level meeting on Iran would be held in Doha on Tuesday with President Donald Trump's top envoys Steve Witkoff and Jared Kushner attending while technical talks would also continue on the sidelines. In a social media post on Monday, Trump said that Iran had requested a meeting and that it would take place in the Qatari capital without giving any details.