The imam leading tens of thousands of worshippers in prayer at Cairo's Tahrir Square on Friday called on the ruling military to hand power to a national salvation government.

Sheikh Mazhar Shahin said protesters would remain in the square -- the symbolic heart of rallies that toppled President Hosni Mubarak -- until their demands were met.

Fierce clashes broke out between rival security forces in the Yemeni capital Friday, two days after President Ali Abdullah Saleh inked a power transfer deal which sponsors had hoped would end the violence.

Dissident troops from the First Armored Brigade led by General Ali Mohsen al-Ahmar exchanged mortar and machinegun fire in the early hours with forces of the central security services commanded by Saleh's nephew Yehya, residents said.

Thousands of supporters of Egypt's ruling military council turned up for a rally in Cairo's Abassiya neighborhood on Friday, just miles from a mass protest in Tahrir Square calling for the end of military rule.

"The military, the police and the people are one," the protesters chanted according to the MENA news agency.

Syrian activists called for demonstrators to flood the streets nationwide after the main weekly Muslim prayers in support of dissident army officers.

"The free army protects us," said a message on the Facebook page of the Syrian Revolution 2011, one of the key motors behind more than eight months of protests seeking to unseat the government of President Bashar Assad.

Russia said Friday ahead of the expiry of a new Arab League ultimatum on Syria that it opposed pressure and sanctions against its traditional Arab ally and wanted to see a renewal of political dialogue.

"At this stage, what we need is not resolutions, sanctions or pressure, but inter-Syrian dialogue," foreign ministry spokesman Alexander Lukashevich told a televised press briefing.

A new Arab League ultimatum which gives Syria until later Friday to agree to accept observers or face sanctions represents a last chance for the regime in Damascus, Turkey's foreign minister said.

"It is a last chance, a new chance for Syria," Ahmet Davutoglu told reporters in Istanbul in the final hours before the 11:00 GMT deadline.

Hamas is looking to focus its energies on popular resistance without giving up its right to wage armed struggle against Israel, the Islamist movement's leader Khaled Meshaal told Agence France Presse in an interview.

"Every people has the right to fight against occupation in every way, with weapons or otherwise. But at the moment, we want to cooperate with the popular resistance," the group's Damascus-based leader said in the interview late on Thursday.

The transfer of power to a civilian government in Egypt must be "just and inclusive" and take place "as soon as possible," the White House said Friday.

"Most importantly, we believe that the full transfer of power to a civilian government must take place in a just and inclusive manner that responds to the legitimate aspirations of the Egyptian people, as soon as possible," White House Press Secretary Jay Carney said in a statement.

Moroccans began voting Friday in the first legislative election since the approval of constitutional reforms that give parliament and the prime minister more powers.

The election, the second in north Africa since the Arab Spring uprisings began, pits the moderately Islamist Justice and Development party against a coalition loyal to King Mohammed VI.

Some 20 Kuwaiti opposition activists detained for storming parliament went on hunger strike on Friday to protest against "illegal and oppressive detention," and maltreatment.

The announcement came in a statement posted on Twitter by the activists' supporters immediately after the public prosecutor extended the detention of 31 activists until Saturday for further investigation.