Gaza continues to be pummelled by blasts, as the possibility of an immediate ceasefire grows more remote, the death toll in Gaza stands at 336, while in Israel three people have died.
Israeli tanks and bulldozers dug in across a mile-wide strip of Gaza's eastern frontier.
Israel sent in ground forces on Thursday after 10 days of air and naval barrages failed to stop rocket fire from Gaza.
The military said its engineers were concentrating on a buffer zone 2.5km wide.
It said they were looking to destroy concealed rocket launch pads and tunnels dug by Gaza's dominant Hamas Islamists after the last big flare-up of violence in 2012.
Hamas said its fighters used one such tunnel to slip into Israel today inflicting casualties.
The Israeli military confirmed the incident near central Gaza, saying it killed one militant, repelled the rest, and four soldiers were injured.
Palestinians also launched at least 18 rockets into Israel killing a man and injuring four people, including two children, in a southern Bedouin Arab village, police said.
On Israel's side, three soldiers and two civilians have died.
Meanwhile, Thousands of protesters with the Ireland-Palestine Solidarity Campaign marched from O’Connell Street to the Israeli embassy to protest Israel's actions in Gaza.
Speakers at a huge rally opposite the Dáil said that any state with trade or diplomatic relations with Israel was complicit in the killings in Gaza
This morning,the Israeli Defence Forces said Hams had taken to attacking soldiers with donkey's laden with explosives.
Hamas attacks Israeli soldiers with explosive donkey http://t.co/CDJpJ90cVU— IDF (@IDFSpokesperson) July 19, 2014
Israel advises citizens to avoid Turkey
Israel has advised its citizens not to travel to Turkey, citing "the public mood" after heated protests there against Israel's ground offensive into Gaza.
The Israeli Foreign Ministry said Israelis should "avoid non-essential visits" to Turkey - once Israel's closest regional ally - or be especially vigilant and steer clear of anti-Israel demonstrations.