Barcelona have been charged with breaching UEFA disciplinary regulations after supporters floated yellow balloons on to the Camp Nou pitch during Wednesday's Champions League victory over Roma.
The La Liga leaders won the first leg of the quarterfinal 4-1 but the match was briefly held up as a result of an apparent political protest in the first half.
Yellow balloons -- potentially representing support for the Catalan politicians who remain in prison following October's unofficial independence referendum -- were released following a wave of pro-Catalan chants in the 17th minute.
Governing body UEFA made no reference to political factors when charging Barcelona on Friday, citing only a breach of Article 16(2), which pertains to the "throwing of objects.''
A statement said the case would be dealt with by the UEFA control, ethics and disciplinary body on May 31.