QALQILYA, West Bank, June 5 (Mohammed Assadi, Reuters) - You are a traitor, grieving mother Um Mohammad Atiyyeh shouted at a Palestinian security man guarding the house where her son, a Hamas militant, was shot dead in a fire-fight in the West Bank city of Qalqilya.
We are executing orders, the man said in response.
Two deadly raids this week by Palestinian President Mahmoud Abbas's Western-backed security forces against Hamas Islamists in Qalqilya have stoked fears of a wider showdown between the rivals in the Israeli-occupied West Bank.
The raids also highlight tension within Palestinian society over Abbas's efforts to fulfil commitments to rein in militants as part of a long-stalled, U.S.-backed road map peace plan.
Hamas, which seized control of the Gaza Strip after routing Abbas's secular Fatah forces in the enclave two years ago, has threatened retaliation after four Islamist militants, four of Abbas's security men and one civilian were killed in the raids.
Underlining the growing tension, Hamas published a hit list for security leaders accused of cracking down on its members, and one of the group's preachers in Gaza called for an intifada, or uprising, in the West Bank against Abbas's men.
U.S. President Barack Obama urged Abbas last month to press on with his security campaign, which he credited with making great progress in the West Bank.
In an address in Cairo on Thursday, Obama urged Hamas to heal the Palestinian rift by putting an end to violence and recognising Israel's right to exist.
Prominent Palestinians issued a joint plea to end the bloodletting and engage in unity talks, expected to resume in Cairo in July.
Worse will come if that dialogue fails, said Palestinian political analyst Hani Masri. What happened in Qalqilya is a result of having two authorities which both claim legitimacy.
Many of Qalqilya's 42,000 residents were shocked by the factional flare-up that quickly engulfed their city, which is closed off from the rest of the West Bank by checkpoints and Israel's cement and steel barrier.
Ihab al-Dalo, a 31-year-old Palestinian labourer who works in Israel, feared more fighting to come because, he said, both sides appeared to be digging in.
The Palestinian Authority won't tolerate Hamas military activities and Hamas is demanding that its members not surrender, Dalo said as scores of security men patrolled outside a building where fighting broke out on Thursday.
Bassam Kharroub, a 45-year-old teacher, defended the raid as part of efforts by Abbas's security forces to maintain law and order and protect and defend our homeland. He said Hamas was to blame for the bloodshed by refusing to give themselves up.
Other residents sided with Um Mohammad Atiyyeh.
We are fighting each other instead of fighting the occupation said Zeina Nazzal, a 29-year-old accountant who described herself as a Fatah loyalist.
This is a scandal. Palestinian people are killing each other for nothing, added Rida Odeh, a 50-year-old merchant.
Other residents said they felt besieged by all sides.
At night we have the Israeli soldiers and during the day we see this, said Ahmad Silmi, pointing to Abbas's men, many of whom have had U.S. and European funded training. (Editing by Louise Ireland) (For blogs and links on Israeli politics and other Israeli and Palestinian news, go to http://blogs.reuters.com/axismundi)