Egyptian fighter jets have crossed into Israeli airspace several times in the last few months as its military continues to battle a militant insurgency in its northern Sinai region. The airspace violations were believed to be the first since the 1973 Arab-Israeli war, and did not elicit a response from Israel’s military, the Times of Israel reported Wednesday.

Israeli officials reportedly labeled the violations “minor,” and it’s possible they were coordinated with the Israeli Defense Forces, according to Ynetnews. The flights were mostly in a triangular border area that connects Israel, Gaza and Egypt.

The Egyptian aircrafts were targeting militant sites miles away from the Israeli border in El Arish and Sheikh Zuweid, areas of the Sinai where a militant insurgent group, the Sinai Province, has been active for months. The group has pledged allegiance to the Syria- and Iraq-based Islamic State militant group, also known as ISIS, and has been responsible for a violent insurgency in Egypt’s restive north.

In late October, the Sinai Province claimed responsibility for a deadly attack on a Russian tourist plane as it left the Sharm el-Sheikh beach resort in the Sinai. All 224 passengers were killed, and militants with ISIS in Iraq released a video of fighters brandishing smiles and handing out candy in celebration of the deaths.

Despite a relative calm between Israel and its neighbors in recent years, Israel has had limited military coordination or diplomatic relations with neighboring countries, and continues to treat entry into Israeli airspace as potential security threats. Warplanes have been deployed to Israel’s northern region dozens of times in the last year amid concerns of Syrian planes crossing into Israel’s territory.

The Sinai Province has recently issued several threats against Israel, whose military and intelligence have increasingly tracked the operations of the militants, gathering information on potential cross-border threats and has said they would be willing to attack the militants if they were planning attacks against Israel. The Sinai Province has thousands of fighters and is one of ISIS’ most active affiliates.