Gunbattles raged between Hamas loyalists and Palestinian President Mahmoud Abbas's Fatah forces in Gaza City on Tuesday (December 18), killing at least three people and reviving fears the Gaza Strip could slip into civil war. Internal Palestinian fighting, the worst in a decade, has escalated since Abbas called for early elections on Saturday in an attempt to break a political deadlock with the Hamas government. Hamas has accused Abbas of launching a "coup". Clashes erupted outside a key security agency controlled by Abbas. A Palestinian security source said the fight broke out when Hamas gunmen fired a rocket-propelled grenade at the compound of the General Intelligence agency. Witnesses and rival factions said a Hamas policeman was killed in the gun fight at the entrance and inside the compound of the main Shifa Hospital in Gaza City. Rocket-propelled grenades were also fired in that incident. The gunbattle began when Hamas police tried to detain security men from Abbas's Fatah faction on suspicion they had been involved in earlier clashes. Hospital officials said the bodies of two security men loyal to Abbas's Fatah had been dumped in a street. Fatah sources said the men were abducted hours earlier by a Hamas-led police unit and "executed". A Hamas police spokesman denied the force had abducted or killed anyone. Five children were also wounded after getting caught in cross-fire. Around a dozen people have been wounded in total. Hamas and Fatah blamed each other for the sudden surge in street fighting in central Gaza City, where gunmen fought running battles with automatic weapons and rocket-propelled grenades. "Yesterday evening there was also a meeting scheduled between us and Hamas and in the presence of the factions and Hamas did not show up for this meeting and there was an escalation in the north and this dawn the kidnapping and firing and armed deployment using RPGs (Rocket-Propelled Grenades) happened this morning at Al Shifa hospital when they detained a group of secret service personnel," a Fatah spokesman Tawfiq Abu Khousa told Reuters. Palestinian Prime Minister Ismail Haniyeh delivered a speech from his Gaza city office on Tuesday (December 19) evening in which he summarized his government's work over the last nine months. "What they were not able to achieve through the siege and the policy of making us fail and here I want to concentrate and I want the Palestinian people to concentrate as well - there is an unannounced decision to make this government fail, there is an unannounced decision to make this government fail and the Americans are leading this policy," Haniyeh told reporters. In response to Palestinian President Mahmoud Abbas's speech delivered on Saturday (December 16) in which he called for early legislative and presidential elections if a unity government cannot be achieved, Haniyeh said: "I reaffirm that we refuse this invitation (for elections) and reaffirm the need to respect the choice of the Palestinian people" Haniyeh finished his speech by calling on Palestinians to strive towards national unity and for an end to the armed internal conflict which is errupting in different neighbourhoods in Gaza and spilling over to the West Bank. "From here I would like to reaffirm the importance of nation a unity, national unity, national unity, national unity, young men of Hamas young men of Fatah, our brothers in the West Bank and Gaza, this is not your battle these bullets do not belong here, this blood is pure and precious and you should preserve your unity and togetherness," Haniyeh told reporters. Hamas and Fatah tried for months to form a unity government to end a power struggle after Hamas beat Fatah in January elections. The clashes have effectively buried a truce in fighting agreed on Sunday night.