By Melih Aslan and Daren Butler
ISTANBUL (Reuters) - Turkish President Tayyip Erdogan and the pro-Kurdish opposition traded blame on Friday over the fate of more than 20 people it says have been trapped for a week in a cellar in a southeastern town as fighting rages between security forces and Kurdish militants.
Six of 28 people trapped in the basement of a residential building, under 24-hour curfew, in the town of Cizre have died over the past week and others are seriously wounded, according to the pro-Kurdish Peoples' Democratic Party (HDP).
Three members of the HDP, the third biggest party in Turkey's parliament, have gone on hunger strike in protest at a failure to rescue the group, whose fate has become a focal point in the region's worst violence in decades.
"If there had been a sincere effort (to get them out) we would not be talking about six dead people today," HDP deputy Idris Baluken told a news conference in Ankara with two colleagues, all on hunger strike since Wednesday.
"We are talking about the problems of our citizens who for seven days cannot find food, water or drugs, who have died due to blood loss because of the lack of intervention."
The fighting, moving into towns scarred by trenches and barricades, coincides with threats from Islamic State militants over the border in Iraq and Syria. NATO allies eager to see restoration of calm in a volatile area have called for a ceasefire and talks to end the conflict.
Thousands of civilians have been caught up in the fighting between the Kurdistan Workers Party (PKK) and security forces that flared after a two-year-old ceasefire collapsed in July.
Baluken said ambulances belonging to the HDP-run municipality in Cizre, near the Syrian border, had tried to reach the group trapped in the cellar on 11 occasions but had been blocked at security force checkpoints.
The building appears to stand on a streetcorner and may lie in the crossfire between military and rebels. Journalists are excluded from the area.
Erdogan rejected the notion that ambulances were being obstructed by the state, blaming the militants and accusing those on hunger strike of being servants of the PKK.
"This is all lies. There are always ambulances there," he told reporters in Istanbul. "They are deliberately not bringing the wounded out," he added.
Turkey, the United States and the European Union all classify the PKK as a terrorist organization. The PKK says it is fighting for autonomy for Turkey's Kurdish minority.
The Turkish army says more than 600 militants have been killed since security operations began in Cizre last month, and denies accusations it has killed large numbers of civilians.
The fighting has caused extensive damage not just in Cizre but also the town of Silopi, near the Iraqi border, and the ancient Sur district of the main city Diyarbakir, enclosed by Roman-era walls which were added to the UNESCO World Heritage list last year. All have been under curfew since December.
The former mayor of Sur said years of progress toward peace in the region were being undone.
"Decades of military policies against the Kurds have shown only that violence begets more violence," Abdullah Demirbas wrote in an op-ed in the New York Times this week.
He likened the scene to neighboring Syria, describing towns "under siege", bodies lying in the street for days and buildings collapsing due to shelling.
(Writing by Daren Butler; Editing by Nick Tattersall and Ralph Boulton)