Hamas, the Islamist movement ruling Gaza, executed three Palestinians Tuesday, whom it had earlier convicted of murder.
"The three men were executed early on Tuesday morning by shooting and not by hanging," said a statement by the Hamas-run Interior Ministry in Gaza, adding that "it wasn't a public execution."
The executions are an escalation in the struggle between Hamas, which controls the Gaza Strip, and Palestinian President Mahmoud Abbas, who controls the West Bank.
Under Palestinian Basic Law, any death penalty must be approved by the Palestinian president, but Hamas does not recognize Abbas' legitimacy and so it went ahead with the executions without Abbas' signature.
They were the first death penalties carried out by Hamas against people found guilty in criminal courts. Over the past nine years, Hamas has executed dozens of Palestinians found guilty in military courts of what Hamas said was collaborating with Israel.
Only representatives of the families of the three murder victims attended the execution, which took place in the southern town of Khan Younis.
The United Nations and human rights groups have expressed alarm, saying they doubt that those executed were given fair trials.
Abbas' West Bank-based administration slammed Hamas' move as "illegal."
A de facto split between the Gaza Strip and the West Bank has been in place since 2007, when Hamas seized sole control of the coastal enclave by violently overpowering security forces answerable to Abbas.
Hamas and Abbas have been entangled in a power struggle since the Islamists won parliamentary elections in 2006, a year after separate presidential elections.
Hamas Attorney General Ismail Jabber told reporters in Gaza last week that the executions would "achieve social justice."
Gaza-based political analyst Naji Shurab said the decision "was made to ease and relax popular pressure" on Hamas in Gaza.
Family members of murder victims have been demonstrating in Gaza during the past two weeks, demanding execution of the murderers of their loved ones.
"Hamas suffers from a crisis in popular trust," Shurab told dpa.