By Tamim Elyan

CAIRO, June 18 (Reuters) - Members of Egypt's constituent assembly vowed to hold their first meeting at the parliament building on Monday in a show of defiance against the army's assumption of legislative powers.

The assembly is due to write a new constitution as part of a transition to democracy engineered by the generals who took power after the overthrow of President Hosni Mubarak's autocratic government last year.

But that transition was thrown into disarray last week when a court of Mubarak-era judges ruled that the parliamentary election was invalid and the chamber must be dissolved.

On Sunday, the ruling military council issued a decree allowing it to write laws and to name a new constituent assembly if necessary, prompting some analysts to say the generals were insuring themselves against a possible Islamist win when presidential election results are announced on Thursday.

Islamists and liberals united to denounce a "military coup" and parliamentary speaker Saad al-Katatni said parliament could only be rendered void by popular referendum.

"We will meet, even if it is on the pavement, unless they use snipers against us," said liberal MP Mohamed el-Sawy, one of the 100 people appointed by parliament to write the democratic constitution.

"We are holding on to this constituent assembly. It is the only gain we took away from the legitimate parliament."



ENTRY BLOCKED

Employees of parliament were under orders to block entry to the building in Cairo after the assembly was declared void last week, members of the defunct parliament said.

Officially, the constitution writing process is unaffected by the removal of parliament.

But the army's decree gives it the right to form a new constitution-writing body if the current one "encounters any obstacles in completing its role" and to oppose any article that contradicts the "goals of the revolution".

"The army will try to use the first opportunity to get rid of it and form a new assembly," said Gamal Abdel Gawad, politics professor at the American University in Cairo.

Analysts say the army might be seeking to secure a special status in the next constitution to protect the economic interests and prestige it has maintained since a 1952 revolution against the monarchy.

The constituent assembly - comprising members of parliament and representatives of professional, labour and other interest groups - planned to choose a head and two deputies on Monday. Sawy said it would show they were pressing ahead with their work.

The assembly's make-up is itself controversial; most liberals and leftists have withdrawn from it because they say it is biased towards the Islamists who dominated the dissolved parliament, and fails to represent Egypt's diverse social groups fairly.

Islamist Mohamed Morsy and former air force commander Ahmed Shafik both claim to have won the presidential election run-off. (Editing by Tom Pfeiffer and Kevin Liffey)

Loading Slideshow...
  • A supporter of Muslim Brotherhood candidate Mohammed Mursi flashes the sign for victory as holds up a Koran, Islam's holy book, during celebrations in Cairo's Tahrir square on June 18, 2012 after Islamists claimed victory in Egypt's first free presidential vote since its uprising. (Photo credit should read MOHAMMED ABED/AFP/GettyImages)

  • Supporters of presidential candidate Mohammed Morsi chant slogans during celebrations claiming victory over rival candidate, Ahmed Shafiq, in Tahrir Square, Cairo, Egypt, Monday, June 18, 2012. (AP Photo/Nasser Nasser)

  • Veiled female supporters of presidential candidate Mohammed Morsi, one carrying a poster with a picture of her son who was killed during the revolution, celebrate the apparent victory over rival candidate, Ahmed Shafiq, in Tahrir Square, Cairo, Egypt, Monday, June 18, 2012. (AP Photo/Nasser Nasser)

  • Two supporters of presidential candidate, Mohammed Morsi ride a motorcycle flying Egyptian flags during celebrations claiming victory over rival candidate, Ahmed Shafiq, in Tahrir Square, Cairo, Egypt Monday, June 18, 2012. (AP Photo/Nasser Nasser)

  • Ahmed Sarhan, media spokesman of Egyptian presidential candidate Ahmed Shafiq's campaign talks in front of Shafiq's poster during a press conference in Cairo, Egypt, Monday, June 18, 2012. (AP Photo/Amr Nabil)

  • Mohammed Morsi and his supporters celebrate his apparent victory in the Egyptian presidential election at his campaign headquarters in Cairo, Egypt, Monday, June 18, 2012. (AP Photo/Ahmed Gomaa)

  • Mohammed Morsi, center, speaks during a press conference after his apparent victory in the Egyptian presidential election at his campaign headquarters in Cairo, Egypt, Monday, June 18, 2012. (AP Photo/Ahmed Gomaa)

  • Egyptian supporters celebrate a premature victory for their presidential candidate Mohamed Morsi, in Tahrir Square on June 18, 2012 in Cairo, Egypt. (Photo by Daniel Berehulak /Getty Images)

  • Egyptian supporters celebrate a premature victory for their presidential candidate Mohamed Morsi, in Tahrir Square on June 18, 2012 in Cairo, Egypt. (Photo by Daniel Berehulak /Getty Images)

  • Supporters of Muslim Brotherhood candidate Mohammed Mursi wave their national flag during celebrations in Cairo's Tahrir square on June 18, 2012 after Islamists claimed victory in Egypt's first free presidential vote since its uprising. (PATRICK BAZ/AFP/GettyImages)

  • Supporters of Muslim Brotherhood candida

    Supporters of Muslim Brotherhood candidate Mohammed Mursi pray on their national flag as others wave flags during celebrations in Cairo's Tahrir square on June 18, 2012 after Islamists claimed victory in Egypt's first free presidential vote since its uprising. Army-backed rival Ahmed Shafiq, who served as prime minister to deposed dictator Hosni Mubarak, disputed the announcement. AFP PHOTO / PATRICK BAZ (Photo credit should read PATRICK BAZ/AFP/GettyImages)