By Daren Butler
ISTANBUL (Reuters) - Turkey's President dismissed suggestions by Prime Minister Tayyip Erdogan that he had exceeded his authority over the handling of a banned protest march, highlighting increasingly open differences between the two.
Erdogan, who has dominated Turkish politics for a decade and overseen unprecedented economic growth, is widely expected to stand for a newly-created powerful executive presidency at elections in 2014. Recent polls, however, present Abdullah Gul as the more popular figure, though he has not expressed any intention to run for the new post.
Erdogan expressed irritation at police failure to prevent thousands of secularists marching in a banned Republic Day rally in Ankara on Monday to protest against what they see as an increasingly repressive and Islamist government.
Police eventually fired tear gas and water cannon to disperse the crowd, prompting Erdogan to question who had ordered them to remove barricades blocking the protesters' path.
"We did not get this country to where it is today with double-headed government and this country will go nowhere in the future with double-headed government," he told a news conference on Tuesday, in a thinly-veiled reference to the presidency.
Gul, a co-founder of the ruling AK Party along with Erdogan in 2001, on Wednesday rejected the idea of a conflict of powers.
"There can be nothing more natural than me as president asking officials that the Republic holiday be celebrated throughout the country in a decent way," Gul said.
"There is no double-headed (government) in the state ... Our constitution and laws clearly state our authority, duty and responsibilities," he told reporters at the presidential palace.
Republic Day marks the foundation in 1923 of the modern Turkish secular republic by Mustafa Kemal Ataturk, whose image the protesters carried on their march. Many secularists see Erdogan, whose party was first elected to power in 1992, as a threat to that secular system - an accusation he denies.
The two men have agreed to disagree in the past on issues including freedom of expression, and officials in Ankara say their relationship is built on deep mutual respect. But their differences are becoming increasingly public.
The frictions risk becoming a distracting feature of Turkish political life as the country grapples with challenges including the impact of war in neighboring Syria, slowing economic growth and a resurgent conflict with Kurdish militants.
Gul criticized Erdogan this month over the detention of members of parliament in alleged conspiracy trials, telling the opening of parliament that deputies in such cases should be allowed to work until final verdicts were reached.
"I don't want to enter into a polemic with our president. It is obvious we don't share the same view," Erdogan told reporters at the time.
Gul's press adviser Ahmet Sever was quoted by newspapers as saying the president, whose calm manner presents him as a more conciliatory figure than the fiery Erdogan, had asked the Ankara governor to show "tolerance" in handling Monday's protests.
Erdogan, who has dominated the political landscape since his Islamist-rooted AK Party swept to power in 2002, has little patience with challenges to his authority. Hundreds of politicians, military, academics and journalists are on trial on charges of plotting against the government.
The prime minister did not directly criticize Gul over Monday's protest, instead blaming police "weakness" and saying he did not believe the president would give such an order to allow a banned rally to pass. But he used the incident to again lay out his case for an executive presidency.
"If a presidential system is brought in we will then take these steps much more easily," Erdogan said.
"Then there will not be such a problem, but aside from that, it is clear what everyone does. My duty as a prime minister is clear and our president's area of duty is clear," he said.
Interior Minister Idris Naim Sahin sought to dispel speculation of a dispute over the issue, telling Milliyet newspaper nobody gave the order for the police barricades to be removed and protesters broke through them in the confusion.
Erdogan is by far the most popular politician with the country's new, conservative-minded middle class, having presided over a decade of unprecedented prosperity.
But recent opinion polls indicate he could face resistance to a bid for an executive presidency planned under constitutional reforms.
Opponents fear that would further consolidate his grip without a parliament strong enough to rein him in. The current presidency is largely ceremonial, though the president must approve laws passed by parliament and makes important appointments in the judiciary and education.
Gul is also popular and the results of a survey by Turkish pollster MetroPOLL last month showed Turks would prefer him as their next president over Erdogan.
Erdogan's supporters warn that if the parliamentary system is not changed, disputes between the president and prime minister will become a regular feature.
"If this system continues, the president and prime minister will clash. This tension will completely dominate the political agenda," parliament speaker Cemil Cicek was reported as telling the editor of Aksam newspaper at the president's Republic Day reception on Monday.
(Additional reporting by Gulsen Solaker in Ankara; Editing by Nick Tattersall and Ralph Boulton)