Egypt's top prosecutor has called for a probe into funds allegedly received by the only serious rival of ex-army chief Abdel Fattah el-Sisi in an upcoming presidential election, sources said.
Investigations started on Tuesday after a lawyer filed a complaint accusing leftist icon Hamdeen Sabbahi of withdrawing a cheque worth $50,200, saying it was given to him by a private company, state-run newspaper Ahram Gate reported without naming the firm.
The AFP news agency also reported that an investigation into payments to Sabbahi from businessmen was under way, citing judicial sources.
Sabbahi, a prominent dissident during the rule of Islamist former President Mohamed Morsi, also contested the 2012 presidential race and finished in third place.
He now hopes to garner support from the divided yet growing opposition to former Defence Minister Sisi in May's elections. However, it is widely expected that Sisi, whose popularity skyrocketed following the ousting of Morsi, Egypt's first democratically-elected civilian ruler, will become the country's next president.
Sabbahi's campaign spokesman Maasum Marzouk told the AFP news agency that a similar complaint was filed during the 2012 election when Sabbahi was accused of receiving "donations for his campaign".
"But the prosecution found nothing at that time. A similar attempt to defame us is being made again," Marzouk said.
Both candidates have kicked off their electoral campaigns and posters supporting Sabbahi have started appearing alongside images of Sisi that have increasingly draped buildings and billboards across Egypt.
Registration of candidates for the elections, scheduled for the May 26 and 27, has entered its second day, and there have been reports of clashes between supporters of both candidates.
The presidential race, the second since the 2011 revolt, comes as the country continues to reel from unrest that has increased since the July coup against Morsi.
Morsi's supporters continue to stage daily rallies which regularly turn violent as security forces use tear gas, bird shot and, allegedly, live bullets to disperse protesters.
At least 31 people were hurt on Tuesday when students of Al-Azhar University's branch in the southern city of Assuit clashed with security forces, officials said.
Fighting was also reported at Cairo's Ein Shams University, while police fired tear gas in the Mediterranean city of Alexandria and in the central city of Mansoura as pro-Morsi students clashed with security forces.
Two people were wounded in similar fighting in the Nile Delta city of Damanhur.
Cairo's Al-Azhar University, where students have been staging daily protests, expelled 25 students, blaming them for violence the previous day.