(Updates with fourth dead)

GAZA, Nov 29 (Reuters) - Israel killed four Hamas fighters in two air strikes in the south of the Gaza Strip on Thursday, Hamas officials and Palestinian medical staff said.

An Israeli army spokeswoman said in one incident, an attack was launched on people wearing military style clothing in an area from which rockets had just been fired towards Israel.

In the second, Israel targeted two men who planted explosives near the fence Israeli forces maintain around the coastal enclave.

Hamas and medical sources said the air strikes were carried out in the Khan Younis area.

On Wednesday, two Hamas security men were killed in an air strike that Israel said was a response to mortar fire.

The Islamist Hamas movement seized control of the Gaza Strip in June after fighting with forces loyal to Palestinian President Mahmoud Abbas.

Shunned by Israel and its Western allies, the enclave's rulers, with about 1.5 million people, have been isolated inside the crowded territory.

Abbas has been in Washington this week attending U.S.-sponsored peace talks with the Israeli government. He and Israel have ruled out negotiations with the Islamists. (Reporting by Nidal al-Mughrabi, writing by Alastair Macdonald; editing by Andrew Dobbie)

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