Syria on Monday accused Turkey of having made a "political and diplomatic gaffe" with its suggestion that Vice President Faruq Al Shara take over from the country's embattled President Bashar Al Assad.
"What (Turkish Foreign Minister Ahmet) Davutoglu said amounts to a flagrant political and diplomatic gaffe," Information Minister Omran Al Zohbi said, quoted on state television.
"We're not in the days of the Ottoman Empire any more. I advise the Turkish government to give up (power) in favour of personalities who are acceptable to the Turkish people," he fired back.
Davutoglu said on Saturday that Shara was "a man of reason and conscience and he has not taken part in the massacres in Syria. Nobody knows the (Syrian) system better than he."
The Syrian opposition, which Turkey supports, "is inclined to accept Shara" in place of Assad, he said on the public television channel TRT.
Meanwhile, Turkey's military Monday struck back at Syrian military positions after a shell fired by the neighbouring country landed in a Turkish border area, a Turkish official told AFP.
Turkey retaliated in kind after the Syrian shell landed in Altinozu district, in southeastern Hatay province, at around 1200 GMT, said the official speaking on condition of anonymity.
"Turkish military retaliates immediately after every single Syrian shell," said the official. "We have anti-aircraft batteries pounding Syrian targets."
Earlier, Hatay's governor said a total of six Syrian shells had hit the Turkish side of the border on Monday, without any casualties.
But it was not immediately clear if the governor's figures included the latest shelling.
"All of them landed in rural areas," said Celalettin Lekesiz, in remarks carried by Anatolia, the state news agency.
The latest incident came on the sixth day of sporadic fire exchange between Turkey and Syria, which was inflamed after Wednesday's deadly shelling fired by Damascus.
Syrian shells hit Akcakale border town in Sanliurfa on Wednesday, killing five nationals. Since then, the Turkish military has responded in kind whenever Syrian fire has breached its territory.
Wednesday's incident was the most serious between Damascus and Ankara since Syrian anti-aircraft fire brought down a Turkish fighter jet in June, and renewed fears of a broader conflict.
The Turkish parliament on Thursday gave the government the green light to use military force against Syria if necessary.
The UN Security Council on Thursday strongly condemned cross-border attacks by Syria and called for restraint between the two neighbours.
Opposition bloc plans massive makeover
The opposition Syrian National Council, often accused of failing to represent the diverse blocs fighting the regime, is planning a major makeover at a meeting in Doha next week, a member said on Monday.
"The secretariat preliminary meetings will begin on the 15th and 16th of October while the council members will hold a meeting on the 17th," SNC member Louay Al Safi told AFP.
"The most important point which will be discussed is restructuring the bloc and expanding it as a further step towards uniting the Syrian opposition under a broader framework," he said.
Safi said new political and civil society groups will join the SNC -- the main opposition bloc -- including a Turkmen bloc and Nasserist socialists "as well as several political blocs, most of them from the revolt groups inside the country."
Twenty-five new NGOs would also join the SNC.
Last month, the SNC agreed to expand to include more opposition groups, but not the National Coordination Committee for Democratic Change, which favours non-violent regime change and opposes foreign military intervention in Syria.
Alya Mansur, a member of the SNC general secretariat, told AFP the council would also elect its secretariat at the Doha meeting which she said will run until around October 20.
The move follows criticism from within and outside the group that it is failing to unite the diverse opposition forces working against President Bashar Al Assad.
The bloc's general assembly will grow from 300 to 400 members and each opposition group will be represented by 20 members, SNC spokesman George Sabra said last month.
The election comes under a reform agreed in Stockholm. The assembly must still choose an executive bureau and leader for the SNC.