* Minister says Islamic State appears in Lebanon for first time
* Says groups encouraged by its gains in Iraq, Syria
* Sees presidential vacuum for at least 6 more months
* Says parliamentary elections "politically difficult"
By Laila Bassam and Tom Perry
BEIRUT, July 10 (Reuters) - The success of the Islamic State in Iraq and Syria has emboldened like-minded militants in Lebanon who believe they can emulate it, the interior minister said, confirming the militant Sunni group had now appeared in Beirut for the first time.
In an interview with Reuters, Nohad Machnouk also signalled there would be no quick end to the political instability buffeting Lebanon. He forecast the country would remain without a president for at least six more months.
Indicating how the country's politics remains hostage to events in the wider region, Machnouk said the fate of the presidency that fell empty in May was out of Lebanese hands.
That suggests no imminent deal between competing states such as Iran and Saudi Arabia that wield influence in Beirut through their alliances with rival Lebanese groups.
Long-standing political divisions among the Lebanese have been exacerbated by the civil war in neighbouring Syria. That conflict has triggered spasms of armed conflict in the north, government paralysis, and a wave of bombings by Sunni militants.
While Lebanese politicians remain divided on many issues, the threat posed by the Sunni militants has spawned rare cooperation between security agencies controlled by competing groups, pointing to shared concern about the danger.
Machnouk said the security forces were coordinating more closely than at any time since the end of the Lebanese civil war in the early 1990s. Their successes included a recent sweep that netted a militant cell affiliated with the Islamic State, which has seized control of large parts of Syria and Iraq.
"I think this is their first official, documented appearance," said Machnouk, a Sunni politician and member of the Future Movement headed by Saad al-Hariri, a Saudi-backed billionaire and Lebanon's most influential Sunni leader.
The cell, rounded up in three separate locations, included a Saudi man who blew himself up when the police stormed a Beirut hotel on June 25. Machnouk said the men had yet to receive instructions on their target.
He assessed the current threat posed by the Islamic State as "individuals and not more".
The Islamic State has declared an Islamic Caliphate in Iraq and Syria in an effort to redraw the borders of the Middle East.
The Lebanese state news agency reported on Monday that 28 people had been charged with belonging to the group and planning attacks. Only seven of them were in custody.
The Islamic State's arrival in Lebanon adds to a list of militant Sunni groups already operating in the country.
Sunni militants have staged numerous bomb attacks in Lebanon since last year, typically targeting areas controlled by Hezbollah, a Shi'ite group backed by Iran that is aiding President Bashar al-Assad's forces in Syria's civil war.
"We must admit that what has happened in Iraq has caused great excitement among these groups that believe they can benefit from the Iraqi experience," Machnouk said.
"They think they can carry out similar operations in Lebanon. But so far, in the last two months, it is clear that the security awareness has been able to obstruct this," he said.
But he added: "The danger of bombings is still there."
PRESIDENCY OUT OF LEBANESE HANDS
Machnouk took office in February, when politicians finally managed to agree on a new government after Lebanon had gone for nearly a year without one. The formation of that government was widely attributed to a deal between Saudi Arabia and Iran on the need to spare Lebanon more political turmoil.
But as yet there has been no such deal on the presidency, a post reserved for a Maronite Christian according to Lebanon's sectarian power-sharing system. Former army chief Michel Suleiman vacated the post in May when his term ended.
While Machnouk did not see the presidential vacuum lasting as long as a year, he said it would take "not less than six months" before the post was filled.
Machnouk said: "The presidential election is a regional and international decision that has so far not been made and will not be made in the near term."
A political deal is needed because none of the rival groups hold enough seats in parliament to secure a quorum for a vote.
He said: "It is linked to all the developments in the region: the situation in Iraq, American-Iranian negotiations, the possibility of Saudi-Iranian negotiations, many things."
Reflecting the political turmoil, parliamentary elections were indefinitely postponed last year because there was no government at the time and the parties could not agree on an election law.
Instead, parliament extended its term until November, 2014. Machnouk played down the chances of legislative elections happening this year.
"It is technically possible, but politically, it is difficult," he said. (Writing by Tom Perry; Editing by Angus MacSwan)