JERUSALEM, Sept 4 (Reuters) - Israeli aircraft struck targets in the Hamas-ruled Gaza Strip on Saturday after Palestinian militants fired a rocket from the territory into Israel, security officials and witnesses said.

The cross-border violence was the first since Palestinian President Mahmoud Abbas and Israeli Prime Minister Benjamin Netanyahu met in Washington on Thursday to relaunch peace talks, and was a stark reminder of the obstacles both leaders face.

Early on Saturday, Gaza militants fired a rocket into southern Israel, causing no injuries, the Israeli military said.

Hours later, witnesses and Hamas security officials said Israeli aircraft fired rockets at targets in Gaza, including smuggling tunnels along the border with Egypt. At least two people were wounded, medical workers said, and two others killed, their bodies retrieved Sunday.

An Israeli military spokesman said he was checking the report.

The Islamists of Hamas routed forces loyal to Abbas to take over the Gaza Strip in 2007. Hamas rejects Abbas's peace moves and said on Thursday that 13 militant groups had agreed to work together to launch more effective attacks against Israel.

Hamas has claimed responsibility for two shooting attacks in the past week in the West Bank, where Abbas holds sway, including one that killed four Israelis. (Reporting by Ari Rabinovitch; Editing by Kevin Liffey)