CAIRO, Apr 24 (Aswat Masriya) - Egypt's interior ministry will tighten security measures on trains and buses and in metro stations, a ministry official said on Sunday, on the eve of planned protests. 

Protests are expected to take place on Monday against the recently signed maritime border demarcation agreement between Egypt and Saudi Arabia. The protests coincide with Sinai Liberation Day, which is a national holiday across Egypt.

Major General Mohamed Youssef, the assistant interior minister for transportation police, told Aswat Masriya that he had instructed the expansion of categories of criminal and political suspicion, which will allow security forces to stop and inspect people who frequent transportation methods on the day of the planned protests.

He added that the interior ministry raised the security alert level to its maximum in preparation for Monday's protests. He also said that all metro stations will be fully operational and will only be shut down depending on situations that might occur.

A border demarcation agreement, which has yet to be ratified by the Egyptian parliament, has stirred controversy in Egypt. Critics argue that the two islands are Egyptian and accuse President Abdel Fattah al-Sisi of "selling Egypt" to Saudi Arabia in return for Saudi aid.

Under the slogan "Friday of the Land", thousands of protesters had gathered in front of the press syndicate on Apr. 15 to protest against the agreement, which stipulates that two disputed islands, Tiran and Sanafir, will be part of Saudi territorial waters.

Protesters ended the demonstration then but said they will resume protesting on Apr. 25.

Several political forces and public figures have called on Egyptians to participate in Monday's protests. They include the Egyptian Social Democratic Party and the Strong Egypt Party, in addition to a number of student groups and youth movements and the two former presidential candidates Hamdeen Sabahi and Khaled Ali.

The now-banned Muslim Brotherhood group has joined in the call for protest as well.

Central security forces will be deployed in large numbers to secure all public facilities, Assistant Minister of Interior for Central Security Forces Medhat al-Menshawy said on Monday

Interior Minister Magdy Abdel Ghaffar warned that security forces will respond with "utmost firmness" to any action that disturbs public security.

Sisi said in a speech on Sunday, in commemoration of Sinai Liberation Day, that the state will firmly stand in the face of attempts to destabilise the country and terrorise citizens.