Syrian regime faced with diplomatic pressure as region calls for reason and a halt to violence

Saudi Arabia, Kuwait and Bahrain have all recalled their ambassadors while Jordan has called for dialogue.

Saudi King Abdullah has also called on Syrian President Bashar al-Assad to urgently implement real reforms.

In a statement on the Saudi-owned al-Arabiya channel, King Abdullah said that events in Syria were "unacceptable" for his country. He said Syria had to choose between "wisdom" or being "pulled down into the depths of chaos and loss".

"The kingdom of Saudi Arabia... demands an end to the killing machine and bloodshed and calls for acts of wisdom before it is too late," he said.

"Syria should think wisely before it is too late and issue and enact reforms that are not merely promises but actual reforms."

Bahrain's Foreign Minister Sheikh Khaled bin Ahmad al-Khalifa also called for "a resort to reason".

In Kuwait, Foreign Minister Sheikh Mohammad al-Sabah said the "military option must be halted" and that "no-one can accept the bloodshed in Syria".

Sabah said the foreign ministers of Gulf states would meet soon to discuss the situation.

Jordan stopped short of condemning the violence, saying it would not interfere in Syria's internal affairs, but Prime Minister Nasser Judeh has said the situation was "worrisome, unfortunate and sad".

"We hope that dialogue is restored and reforms are achieved in order to get Syria out of this impasse," he said in a televised statement.

The 22-member Arab League issued its first statement on Syria on Sunday. It said it was "alarmed" and called for an end to the violence.

The League's head Nabil al-Arabi said he hoped the crisis could be overcome "by peaceful means and by launching a serious dialogue towards the reconciliation that the people have been demanding".

"When people take to the streets... and seek change, presidents and governments must reach that solution through dialogue without making use of violence or force," he told reporters.

But he said "drastic measures" should not be expected, and stressed that the League would not take action itself.

Turkey also stepped up the pressure, with Foreign Minister Ahmet Davutoglu due in Damascus on Tuesday with a "tough" message for Assad.

Meanwhile the top Sunni Muslim authority, Cairo-based al-Azhar, said the situation in Syria had "gone too far" and added that  “there is no other solution but to put an end to this Arab and Islamic tragedy.”

"The vast repression, the use of the highest levels of violence, arrests and intimidation represent an unacceptable human tragedy."

The pressure comes as government tanks have been pounding the eastern city of Deir al-Zour for a second day.

At least 50 people died on Sunday after the army launched a pre-dawn assault - activists said the explosions and gunfire resumed early on Monday.

Activists said that as in recent days, many people had been afraid to leave their homes or take injured people to hospital for fear of being attacked themselves.

Human rights activists say at least 1,700 civilians have been killed and tens of thousands arrested since the uprising began in mid-March. More than 300 people are believed to have died in the past week alone.

Access to Syria has been severely restricted for international journalists and it is rarely possible to verify accounts by witnesses and activists.