Palestinian gunmen from the Palestinian Popular Front for the Liberation of Palestine-General Command stand outside their base, where an Israeli warplane attacked one of their tunnel entrances, near the Mediterranean coastal town of Naameh, Lebanon, Aug. 23, 2013. (Hussein Malla/AP)

Israel said it bombed a militant group’s base in Lebanon on Friday in response to the launching of four rockets across its northern border hours earlier. It was Israel’s first airstrike inside Lebanon since its 2006 war with the Lebanese militant group Hezbollah.

The target was a base belonging to the Popular Front for the Liberation of Palestine General Command located near the town of Naameh, just 10 miles south of Beirut, Lebanon’s state news agency reported.

The Popular Front denied any involvement in the rocket attack inside Israel, for which an al-Qaeda-linked organization had already claimed responsibility.

The escalation comes at a time of increased tension between Lebanon and Israel, with four Israeli soldiers injured in an explosion near the border earlier this month. In a statement, the Israeli military described the rocket attack on Thursday as “a blatant breach of Israeli sovereignty that jeopardized Israeli civilian life.”

An Israel military spokesman said that the pilots who carried out the airstrike “reported direct hits on the target” adding that “Israel will not tolerate terrorist aggression originating from Lebanese territory.”

A journalist at the scene for Lebanon’s Daily Star newspaper said the entrance to one of a series of underground tunnels belonging to the PFLP-GC was damaged in the raid.

Speaking to Lebanon’s al-Manar television station, Abu Imad Ramez Mustafa, a PFLP-GC official, said he was surprised they had been targeted when another group had claimed responsibility for firing the rockets.

On Thursday, the Lebanese branch of the Abdullah Azzam Brigades, an Islamist group with links to al-Qaeda, said it had carried out the rocket attack. The group, known as the Ziad al-Jarrah Battalion, is named after a Sept. 11, 2001 hijacker who was from Lebanon.

“Praise and thanks be to Allah,” read a post on a Twitter account known as an outlet for the group, which has asserted responsibility for firing rockets into Israel in the past.

Israeli military officials said the missiles fired into its territory appeared to be short-range ­Katyusha rockets. One was downed by Israel’s Iron Dome defense system, which is partly funded by the United States. Israel’s Channel 2 reported that another of the rockets narrowly missed landing on a retirement home near the city of Acre for Jewish survivors of the Holocaust.

The rockets were fired from the vicinity of the Rashidieh Palestinian refugee camp near the southern Lebanese city of Tyre, Lebanon’s National News Agency reported.

“Anyone who attacks us, or tries to attack us, should know that we will get him,” Prime Minister Benjamin Netanyahu warned. The Israeli leader said the military and home defense unit were deploying “defensive and preventative” measures.

Dina Badawy, a deputy spokeswoman for the State Department, condemned the rocket attack into Israel, telling the Jerusalem Post, “This was a provocative act that undermines the stability of Lebanon and the security of Israel.”

She urged Lebanon to exercise full sovereignty over its territory and called for restraint by all parties.

Rockets were fired at Israel last year but fell short of entering the country. In 2011, rockets reached Israel and damaged two buildings.

With air raid sirens blaring and civilian air traffic halted, the rocket attack Thursday rekindled memories of the 34-day Israel-Lebanon war in 2006, when Hezbollah fired as many as 4,000 rockets into northern Israel. In response, Israel developed its Iron Dome missile interceptors, deploying the mobile units in 2011.

“Israel’s defense system is better than during the Second Lebanon War, and the Iron Dome has proved itself,” said Arieh Herzog, former head of Israel’s missile defense program.

“However, Israel does not have enough batteries to protect every one of its cities. Israel is working to produce more Iron Domes with the help of the United States,” he said.

Some Israeli politicians had publicly called for a retaliatory strike. “The response must be very strong so that the other side has no desire to continue the escalation,” said Motti Yogev, a lawmaker from the Jewish Home party, told the Jerusalem Post.

This month, four Israeli soldiers were injured in an explosion along the border with Lebanon. The Lebanese army said the soldiers were hurt inside Lebanon. Israel military officials have been vague about the soldiers’ exact location.

Booth reported from Jerusalem.