Some 5,000 police were on duty in Diyarbakir, the largest city of the Kurdish-majority southeast, where Recep Tayyip Erdogan was to speak later in the day, among them snipers positioned on rooftops around the meeting square.

A small group of youths hurled several petrol bombs and firecrackers in a neighbourhood away from the square, but were quickly dispersed by the police, an AFP reporter said.

Speaking in Istanbul before his departure, Erdogan announced projects to boost economic and social development in the impoverished region.

"We continue to expend efforts -- with patience and determination -- to increase investment in the (Kurdish) region and resolve its problems," Erdogan told a gathering of his Islamist-rooted Justice and Development Party (AKP).

The government, he said, will renovate Diyarbakir's historic walled city, build a new airport, a dam, a stadium, more hospitals and highways as well as recreation facilities on the banks of the Tigris river in the city outskirts.

Tensions have mounted between Ankara and the Kurds ahead of the June 12 elections amid a renewed military onslaught on the separatist Kurdistan Workers' Party (PKK) and deadly PKK attacks on police despite a truce the rebels declared last year.

The vast majority of shops in Diyarbakir remained open Wednesday in contrast to an earlier rally Erdogan held in the region when almost all businesses closed in a traditional Kurdish protest against the state.

A police helicopter overflew the city and the security forces, aided by sniffer dogs, checked people who arrived to the meeting venue.

Drawing on cultural reforms, improved services and a sentiment of Islamic fraternity, the AKP has enjoyed solid popularity in the southeast and has about 70 Kurdish lawmakers in the outgoing parliament.

The government however has failed to meet Kurdish demands for broader political freedoms and to cajole the PKK into laying down arms.

Kurdish frustration has grown amid a massive probe into a purported urban extention of the PKK, which has landed hundreds of Kurds, among them mayors and prominent activists, in jail.

Nationalist Kurdish candidates, backed by the Kurdish Peace and Democracy Party (BDP) which is seen as close to the PKK, are the AKP's main election rival in the southeast.

Erdogan has accused the BDP of collaborating with the PKK, which Ankara lists as a terrorist group, and orchestrating violent protests, in which Kurdish youth routinely pelt police with petrol bombs and vandalise public property.

A series of EU-inspired reforms have broadened cultural freedom for Turkey's Kurds in recent years: they can today broadcast in Kurdish, teach their language in private courses and use it in political life.

But the Kurds now want autonomy and the PKK appears bent on pressing the demand with arms.

Jailed PKK leader Abdullah Ocalan, who retains his influence despite behind bars since 1999, has warned that "all hell will break loose" unless sporadic contacts officials had had with him in prison are upgraded to full-fledged negotiations to resolve the Kurdish conflict.