Roger Stone, former political adviser of U.S. President Donald Trump, departs after a hearing where Stone said he had "abused" a gag order with an Instagram post that appeared to threaten U.S. District Court Judge Amy Berman Jackson, who is presiding over his criminal trial, at U.S. District Court in Washington, U.S., February 21, 2019. REUTERS/Carlos Barria

WASHINGTON (Reuters) - The federal judge overseeing the criminal case of President Donald Trump’s former political adviser Roger Stone on Thursday tightened a gag order against him and threatened Stone with jail if he violates it.

Judge Amy Berman Jackson of the U.S. District Court for the District of Columbia stopped short of revoking bail conditions for Stone, but she ordered him not to speak publicly about the case related to the investigation of Russian election interference, address it on social media or comment on it indirectly through surrogates.