Smoke billows from an Egyptian naval vessel on the maritime border between the Gaza Strip and Egypt, July 16, 2015. The Egyptian military said a coast guard vessel had exchanged shots with militants off the coast of northern Sinai. The boat caught fire but the incident resulted in no casualties, the military said. (Hatem Khaled/European Pressphoto Agency)

An Islamic State affiliate claimed a missile attack on an Egyptian navy vessel Thursday, raising concerns that the emboldened jihadists can now threaten this country’sstrategic waterways.

In an online statement, the militants said they used a guided missile to hit the ship off the shore of Egypt’s restive Sinai Peninsula. The group — which calls itself the Sinai Province of the Islamic State — also circulated photographs that appeared to show the projectile flying toward the vessel and exploding on impact. In the pictures, the blast sends a fireball into the sky. Egypt’s military said in a statement that a shootout with militants had set the vessel aflame and that no sailors were killed in the attack. Sinai Province claimed to have destroyed the naval frigate.

Egypt’s insurgents have launched a number of attacks on security forces since the military ousted the country’s elected Islamist government in 2013. But if the Islamic State-affiliated jihadists can maintain strikes on naval targets, analysts said, they could threaten Egypt’s shipping lanes and deal a serious blow to the country’s image as a stable power in the region.

The Egyptian government relies on about $5 billion in annual revenue from the Suez Canal, which connects the Mediterranean to the Red Sea. The canal is operated under tight security, but at least one jihadist cell attacked a commercial ship there in 2013. In November, assailants in a fishing boat opened fire on an Egyptian navy vessel off the coast of the northern city of Damietta. Eight sailors remain missing from that incident.

This image posted on a militant social media account affiliated with the Sinai branch of the Islamic State on July 16, 2015, shows an object, seen inside circle drawn around it, that the group claims is a rocket headed for an Egyptian navy vessel during an attack claimed by the group, off the strategic peninsula's Mediterranean coast. ( /via AP)

Egypt’s Sinai-based militants swore allegiance to the Islamic State last fall, after operating for years as a local insurgent group. It is unclear whether the militants have received resources or training from the Islamic State’s central leadership in Syria and Iraq. There, the jihadists hold wide swaths of territory, while most of the local affiliate’s attacks are confined to the Sinai Peninsula.

Security experts say the weapon fired at the naval frigate Thursday was probably a guided anti­tank missile, a sign of the militants’ expanding arsenal. The missile has a range of about five miles, experts say.

“We have a serious threat [from militants] along our coast, and this shows the urgency of it,” said Hisham Kassem, a Cairo-based political analyst.

Egypt borders Libya, the Gaza Strip and Sudan, all of which are wracked by conflict and awash in heavy weaponry. Islamic State loyalists in recent months, and al-Qaeda-linked militants have operated in eastern Libya for years. People have used the poorly patrolled Egypt-Gaza maritime border to cross back and forth and avoid a strict Israeli-Egyptian blockade.

Egypt is a major recipient of assistance from the U.S. government, with $1.3 billion allocated for fiscal 2015.

Military aid from the West “is now going mainly toward border security and maritime security” in Egypt, Kassem said. “That is very telling.”

“The Egyptian military needs to recalibrate,” he added. “It needs to understand the threat.”

This image posted on a militant social media account affiliated with the Sinai branch of the Islamic State group on July 16, 2015 shows smoke rising from an Egyptian navy vessel during a rocket attack claimed by the group. ( /via AP)

Thursday’s attack was the latest in a series of high-profile operations carried out by militants across Egypt. The attacks in recent weeks have put the country on edge, and officials have vowed to expand a crackdown that has already netted thousands of dissidents.

Since late June, militants have targeted senior Egyptian officials, as well as police and army outposts.

On June 29, a car bomb killed the country’s attorney general near his residence in the capital. The slain prosecutor was responsible for all criminal ­cases, including those that have sent scores of Islamists to prison. His killing marked the first high-profile assassination here in decades.

Two days later, Sinai Province gunmen stormed multiple army checkpoints near the Sinai city of Sheikh Zuweid, drawing security forces­ into a day-long urban battle that left 17 soldiers dead, the military said. The Egyptian military responded with airstrikes in the area and has claimed to have killed more than 100 militants.

A car bomb exploded outside the Italian Consulate in Cairo on July 10. The Islamic State said it was a warning to Italy to refrain from intervening in Libya.

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