Russia's U.N. envoy said Tuesday he has handed over evidence to the United Nations which indicates Syrian rebels used sarin gas in an attack in March.

The envoy, Vitaly Churkin, said Russian experts had been to the scene of the attack at Khan al-Assal near Aleppo and had gathered firsthand evidence.

Egypt's armed forces warned on Tuesday against any attempt to disrupt the country's "difficult and complex" transition.

The statement, read out on state television, comes almost a week after the army overthrew Islamist president Mohammed Morsi and appointed top judge Adly Mansour as caretaker leader.

The new head of the Syrian National Coalition has backed calls for a truce from U.N. chief Ban Ki-Moon during the holy month of Ramadan.

Ahmad Assi Jarba, who was elected to the post on Saturday, said he hoped all parties in the civil war would abide by any truce.

The United Arab Emirates said on Tuesday it has offered Egypt an aid package of $3 billion, just days after it hailed the ouster of Islamist president Mohammed Morsi by the Egyptian army.

The package includes a grant of $1 billion and a $2 billion interest-free deposit in Egypt's central bank, WAM state news agency said.

The Egyptian authorities were set to reopen the Rafah border crossing with Gaza, which has been closed since Friday, to allow entry to the territory, the Hamas government that rules the Palestinian territory said.

"The crossing will be open tomorrow from 8:30 am until 2:30 pm (Wednesday from 0530 GMT until 1130 GMT) for arrivals, and for departures only for the sick and holders of Egyptian or foreign passports," Hamas's deputy foreign minister Ghazi Hammad said in a statement.

Egypt's Tamarod campaign, which launched the protests that prompted the ouster of president Mohammed Morsi, called on Tuesday for changes to a proposed interim charter, their spokesman told AFP.

Mahmud Badr said his group was drafting proposed amendments to the temporary constitution unveiled earlier on Tuesday by army-installed caretaker President Adly Mansour which sets out a blueprint for a political transition.

Britain is to train up to 2,000 Libyan troops in a bid to "help them achieve peace and stability across their country", the British defense ministry announced on Tuesday.

"The UK armed forces are to train their Libyan counterparts in basic infantry skills and leadership training with courses beginning later this year," the ministry said in a statement.

Saudi Arabia threatened on Tuesday to expel non-Muslim expatriates who eat, drink, or smoke in public during the Muslim fasting month of Ramadan.

Ramadan begins in the kingdom on Wednesday.

Syrians travelling to Egypt are now required to apply for a visa, after the authorities in Cairo issued a new rule amid soaring unrest in the country, consulate staff in Beirut told Agence France Presse on Tuesday.

"There is a decision from Cairo that any Syrian travelling to Egypt must apply for a visa at the Egyptian embassy," a staff member at the Egyptian consulate in Beirut said.

Russia on Tuesday urged "free and fair" elections in Egypt that would stabilize the restive country after the ouster of president Mohammed Morsi and continuing violent protests.

"We support all efforts directed at ending the violence and confrontation" and moving toward "transparent and inclusive ... free and fair elections," Foreign Minister Sergei Lavrov said.