"We are one Palestinian people in Gaza and the West Bank ... Abbas is helping the Israelis by jailing his own people."
The protest came amid simmering tensions between the two Palestinian factions after Hamas defeated Fatah-led forces in the Gaza Strip in June, prompting Abbas to sack a Hamas-led government.
Abbas has since established a new administration in the West Bank headed by prime minister Salam Fayyad, which has the backing of Western governments.
Mona Munsoor, a Hamas politician, said about 150 Hamas supporters had been jailed by Fatah-aligned forces in the West Bank for political reasons.
"The conditions are very harsh and they have been beaten," Munsoor told Reuters news agency.
"We, the mothers, want to show the world what Fatah is doing to us."
Saturday's protest was the first by Hamas supporters in Ramallah since the fighting in Gaza in June.
Tensions between the factions have been particularly high in Gaza in recent weeks after Hamas security men beat Fatah supporters during protests and Hamas blamed mysterious explosions on Fatah loyalists.
Sami Abu Zuhri, a Hamas spokesman told the AFP news agency: "The attacks by the Palestinian Authority security services against a peaceful demonstration organised by mothers and wives shows the repression being carried out by the Ramallah regime against Hamas in the West Bank, even against its women."
Hamas said that security forces loyal to Abbas had detained a further six of its members in the northern West Bank in the previous 24 hours, including two municipal councillors in the city of Nablus.