Bodies of two teenage Palestinians, with bullet holes in them, have been found in the southeast of Gaza City, Palestinian medics say.
The two were identified as Salah Abu Attwa and Imad Faraj, both 17. They were buried later on Sunday, AFP reported.
An Israeli military spokeswoman said Saturday night the army had opened fire on two men who were spotted moving toward a frontier "no-go zone."
Israeli troops frequently open fire on Gaza residents, who resort to collecting scrap metals to make a living under the crippling Tel Aviv-imposed blockade.
The Israeli military launches attacks on the Palestinian territories on a regular basis.
At the turn of 2009, Israel invaded the impoverished Palestinian stretch of land, killing more than 1,400 Palestinians, mostly women and children.
The attack code-named "Operation Cast Lead" also inflicted a $1.6 billion damage to the Gaza economy.
In a statement on Sunday, Hamas said Israel is escalating the situation to "try and derail reconciliation efforts to restore the unity of the Palestinian people."
Some 1.5 million people in the Gaza Strip are being denied their basic rights, including freedom of movement, and their rights to appropriate living conditions, work, health and education.
Poverty and unemployment rates stand at approximately 80 percent and 60 percent in the Gaza Strip respectively, reports say.