Three armed Palestinians were killed early Monday in clashes between Hamas and Fatah gunmen in southern Gaza, Palestinian security officials said, the most serious outbreak of violence between the two. A Hamas fighter was killed first in the clashes in the town of Bani Suheila, near the city of Khan Younis. Then Hamas fighters fired an anti-tank rocket at Fatah gunmen, killing two. Fatah officials said five of their men were captured. Hamas and Fatah gunmen have had sporadic clashes since Hamas took over the Palestinian government following an election victory in January.