Cairo  - Many privately owned pharmacies were engaged in a second day of strikes Tuesday in a row to protest efforts by authorities to enforce a new tax law.

Some pharmacies had signs on their closed doors saying: "The pharmacy is closed in protest against the bad treatment of the Income Tax Authority against the Egyptian people."

At issue is the Tax Authority's demand for back taxes dating from 2005. Under a deal struck that year between Egypt's Pharmacist Syndicate and the Ministry of Finance, private pharmacies' lost their tax status as small businesses, meaning a jump in tax duties.

Although the deal was reached in 2005, it only went into effect a few weeks ago. However, many pharmacies claim they have not kept adequate records in the intervening years. The Tax Authority has threatened trials for pharmacies that do not comply with its request for records.

Egyptian Minister of Health Hatem al-Gabali on Tuesday asked public pharmacies to remain open 24 hours a day to counter the effects of the strike.

On Monday, the Pharmacist Association had a meeting to discuss the situation.

Standing in front of a placard saying: "The ghost of taxes eats away the income of honest Egyptians," Mahmoud Abdel-Maqsoud, the Secretary General of the Association promised that the strike will continue until next Saturday.

"The pharmacist will bring the end of this government soon," Abdel-Maqsoud was quoted as saying in remarks published by the English-language weekly Egyptian Mail on Tuesday.

Union strikes are not uncommon in Egypt and sometimes lead to violence.

As pharmacists were discussing measures to pressure the government, truck drivers and owners went on strike on Monday, following a draft law that would ban the use of large trailers for safety reasons.

Violence escalated in al-Gharbiya governorate as the strike continued. Angry drivers threw heavy rocks at trailer drivers who refused to strike. At the same time, police detained 11 drivers for investigation.

On Sunday, 18 people were injured, including three policemen.

Last April, thousands of citizens staged violent riots in the northern city of Mahalla over low salaries and rising prices. At least three people were killed during the protests. While dozens were injured, around 400 were arrested. (dpa)