The child was named as Abd al-Qader al-Badrasawi. He had been wounded by Israeli tank fire last Thursday in Khan Yunis, in the southern Gaza Strip.
Said Qassem, 42, died of injuries he sustained six months ago when Jewish settlers opened fire in his direction near the northern West Bank town of Jenin.
The medics said Qassem, a mentally retarded man, had been wandering close to Jenin's nearby settlement of Sanur.
Their deaths brought to 3502 the number of people killed during the three-year-old Palestinian Intifada, including 2617 Palestinians and 822 Israelis, according to a count by French news agency AFP.
The news came during the Jewish holiday of Yom Kippur, with tensions already high due to the total closure of the Palestinian territories by the Israeli army and continued raids on residential areas.
Israeli forces arrested seven Palestinians on Sarurday during a crackdown in the villages of Bait Rima and Kafar Ein, 20 km northwest of the West Bank city of Ram Allah, Aljazeera reported.
More than 10 Israeli military vehicles stormed the two villages early on Saturday, and Israeli forces searched several houses for Palestinian resistance fighters, eyewitnesses said.
On Friday, the Israeli army wounded three Palestinians and arrested around 20 more in a raid on a village near the northern West Bank city of Jenin.
Palestinian security sources said the three, all cafe workers, were injured when troops stormed Qabatiya.
An Israeli military source said that throughout Thursday Palestinians in Gaza had fired an array of anti-tank missiles, mortars and grenades at troops and Jewish settlements in the area.
Two were arrested by the Israeli army while the third was taken to a Palestinian hopsital. The soldiers also hauled in 20 patrons.
The army confirmed the operation and said it shot the three as they tried to escape the sweep.
Earlier in the day 16 people were arrested elsewhere in the West Bank with the Israeli army claiming they were resistance fighters.
The shootings and arrests followed the killing Thursday night of a 60-year-old man as he walked home in the southern Gaza Strip.
Salim Bayumi was walking just outside his home in the border town of Rafah when a sudden burst of gunfire erupted from an Israeli tank, said Palestinian medical sources.
Bayumi was hit in the chest and died shortly afterwards.
Four other Palestinians, two men and two women aged between 60-65 were injured.
An Israeli military source said that throughout the day Palestinians in the area had fired an array of anti-tank missiles, mortars and grenades at troops and Jewish settlements in the area.
Troops had generally returned fire, he said, but he had no knowledge of casualties.