By Nidal al-Mughrabi
GAZA (Reuters) - Israeli aircraft struck targets in the Gaza Strip on Thursday, a day after Palestinian militants fired more than a dozen rockets and mortar bombs across the border and deep into Israel.
The upsurge of violence on the Gaza border in the past few days has led to fears of a new war between Israel and the Islamist group Hamas, which governs the Gaza Strip, after months of relative quiet.
Hamas said Israel's latest attacks targeted smuggling tunnels along the Gaza-Egypt border and one of its training camps in central Gaza.
A third strike hit a power transformer, causing blackouts in the area, witnesses said. Medical workers said no one was injured in the strikes. Hamas said it ordered its personnel to evacuate their positions.
The Israeli military said the strikes were a response to a recent barrage of rockets.
Hours later, Israeli aircraft fired on "a group of terrorists preparing to launch rockets at Israeli territory," a military spokeswoman said. No injuries were reported.
Violence along the Gaza border has spiked in recent days and a bomb attack on Wednesday in Jerusalem that Israeli police blamed on Palestinian militants killed one woman and injured 30 people. It was the first such attack in the city since 2004.
Britain identified the woman as a British national and Israeli police said she was a tourist.
In the Israeli-occupied West Bank, the Islamic Jihad militant group said two of its leaders were detained by security forces of the Western-backed Palestinian Authority for questioning about the bombing. No group claimed responsibility for planting the bomb, which exploded near a bus stop.
More than a dozen rockets and mortars were fired from Gaza into southern Israel on Wednesday, some reaching the cities of Beersheba and Ashdod, 35 km (20 miles) and 40 km (25 miles) away respectively, the military said.
"The responsibility lies entirely on Hamas... we know how to act and have proven this in the past, we will strike proportionally when needed," Israeli Civil Defense Minister Matan Vilnail told Israel Radio.
Hamas says its attacks in the past week have been in response to Israeli strikes. Five Palestinian militants and four civilians, three of them children, were killed by Israeli fire in the Gaza Strip on Tuesday.
Israeli Prime Minister Benjamin Netanyahu warned militant groups in the Gaza Strip on Wednesday that Israel would act decisively to defend itself.
He threatened a lengthy "exchange of blows" with Palestinian militants, though officials from both sides have said they want to prevent a repeat of Israel's 2009 three-week war on the coastal enclave.
Israel, which launched that campaign with the declared aim of ending cross-border rocket fire, killed around 1,400 Palestinians, drawing heavy international censure. But Hamas has mostly held fire since then.
(Writing by Ari Rabinovitch and Maayan Lubell, editing by Tim Pearce)