Egypt's benchmark EGX30 index resumed its downward spiral on Sunday, shedding a further 1.03 percent to land at 4,603 points and bringing year-to-date losses to 15.72 percent.

The index had picked up somewhat during last week's closing session on Thursday, after hitting a one-year low on Wednesday.

Daily turnover, meanwhile, reached its lowest level in years on Sunday, registering a mere LE72.2 million.

"Foreign and Arab investors are on standby, waiting until the political situation becomes clearer," Ashraf Abdel-Aziz, head of institutional sales at Cairo-based Arabia Online Securities, told Ahram Online.

The prospect of nationwide anti-government demonstrations, planned for the end of this month by Egypt's opposition 'Rebel' campaign, has greatly unnerved investors, according to analysts.

Campaigners, who have been working since May to gather 15 million signatures aimed at unseating Islamist President Mohamed Morsi, plan to march to the Presidential Palace in Cairo to demand his ouster on 30 June, which will mark the end of his first year as president.

Egyptian Financial Supervisory Authority head Ashraf El-Sharkawy told Reuters on Sunday that the Egyptian Stock Exchange would remain open on 30 June, "given that the banks and telecommunications will be operating normally."

"There are several measures that can be taken to protect the market if the necessity arises," El-Sharkawy added, although he refrained from specifying what these measures might be.

Authorities closed the local stock market for nearly two months in early 2011 after the outbreak of the Egyptian uprising sent stocks plummeting 18 percent over two trading days.

The threat of Egypt's exclusion from the Morgan Stanley Capital International Index (MSCI) eventually forced the market to reopen, and it has not been closed again since despite several episodes of political unrest and market losses.

Egyptian investors, who accounted for nearly 80 percent of market activity on Sunday, were net sellers to the tune of LE11.9 million.

Most of the stocks listed on the EGX30 ended the day in the red, led by luxury real estate developer SODIC, which fell 4.15 percent. The rest of the real estate sector also suffered, with TMG Holding falling 1.3 percent and Palm Hills Development Company down 1.24 percent.

Orascom Construction Industries (OCI), Egypt's largest listed company, fell by 1.57 percent, while Orascom Telecom slumped by 1.24 percent.

Blue-chip stock Commercial International Bank, meanwhile, slid 0.67 percent, while leading investment bank EFG-Hermes fell 1.12 percent.