Jerusalem ? Israeli troops killed two Palestinian militants in a shootout Friday, while Palestinian leader Mahmoud Abbas’ Fatah movement appeared to be making an unexpectedly strong showing against rival Hamas in local elections in dozens of West Bank towns and villages.

Hamas said the results were preliminary and it was too early to judge. The Islamic militant group also complained that many of its candidates were detained by Israeli troops before Thursday’s election. The arrests are part of Israel’s weeklong campaign against militants, triggered by rocket fire from Gaza on Israeli border towns.

Armed groups have threatened revenge, and an informal seven-month-old truce could collapse as a result of the escalation.

Two Palestinians were killed and another seriously injured, according to witnesses and Palestinian officials. The gunmen were from the Al Aqsa Martyrs’ Brigades, a militant group with ties to Fatah.