U.S. President Donald Trump called Hizbullah a threat to Lebanon and the entire Middle East on Tuesday, accusing it and Iran of fueling a humanitarian disaster in Syria.

The Lebanese authorities must “disclose the full findings of their investigation” into the deaths of four Syrian detainees, Amnesty International said Tuesday, after the country’s military prosecutor revealed Monday that a forensic report concluded that they had died of “natural causes.”

The Internal Security Forces arrested during search raids in Beirut and the Bekaa valley, a five-member cell involved with the Islamic State terror group, the ISF said in a statement on Tuesday.

Hizbullah fighters have made “additional gains” in their fight against al-Nusra Front militant group along the eastern border with war-ravaged Syria, and plan to wage an assault against the Islamic State organization located on the other side of the outskirts, media reports said on Tuesday.

LBCI said that Hizbullah was able to seize control on Tuesday of Wadi Kamil, Wadi Hammoudi, Makaabat al-Forn, al-Baydar, Shaabat al-Nahle and Wadi Dalil al-Barak, in Arsal's outskirts.

Speaker Nabih Berri lauded the “efforts” of the Resistance fighters as he assured that they are battling al-Nusra Front militants in the outskirts of Arsal “on behalf of Lebanon and the Lebanese,” al-Joumhouria daily reported on Tuesday.

State Commissioner to the Military Court Judge Saqr Saqr on Monday said that a medical report he received on the death of four Syrian refugees showed they deceased as the result of chronic health problems, the State-run National News Agency reported.

Saqr received the report from a medical committee tasked with investigating the reasons leading to the death of four Syrians who were taken into the army's custody.

Hizbullah's leadership announced on Monday that its “operation” against al-Nusra Front terror group entrenched in the outskirts of Arsal was "about to end," as it “urged militants to surrender” after seizing control of the majority of the group's strongholds.

Lebanon's military and security agencies have taken the needed measures following threats that some “sleeper cells” committed to terror groups in the border town of Arsal could mobilize against the army in kidnap operations, al-Joumhouria daily reported on Monday.

A military source who spoke on condition of anonymity told the daily that “confessions made by one of the detainees said that sleeper cells in a number of encampments in Arsal, around 150 members, were planning to carry out security operations against the army's units deployed in the area, cutting off all supply and communication routes.

On the second day of its operation against al-Nusra Front militant group entrenched on the outskirts of the border town of Arsal, Hizbullah was able to secure gains, the National News Agency reported on Saturday.

Hizbullah fighters “secured gains as they caught the hills of Wadi al-Khayl and al-Qanzah following heavy clashes with the Nusra terrorists,” NNA said.

The results achieved on the first day of an operation launched by Hizbullah against militants on both sides of the country's border with Syria, indicate that the “battle could reach fruition in a time period shorter than anticipated,” al-Joumhouria daily reported on Saturday.