Saudi Arabia, which has strongly criticised President Bashar al-Assad’s regime, last week closed its Damascus embassy and recalled its diplomats.
Reports claim the Saudis have been sending military equipment via Jordan to the rebel Free Syrian Army.
Amman has categorically denied the claim.
Russia meanwhile has called on Syria to back ‘without delay’ the peacemaking efforts of the international envoy Kofi Annan.
Some observers say it shows Moscow taking an unusually firm line with Assad’s regime.
Violence continued to rage amid mass anti-government protests in the eastern city of Raqqa, according to new amateur video which cannot be verified.
Human rights monitors claimed five people had died.
It is not clear whether humanitarian observers from the UN and the Organisation of Islamic Cooperation, in a joint mission with the Syrian government, will begin a planned assessment of needs across the country.