Georgia on Thursday arrested the personal photographer of President Mikheil Saakashvili and three other photojournalists for allegedly spying for a foreign country, the interior ministry said.

Officials did not name the country involved but Georgia's pro-Western administration has repeatedly accused arch foe Russia of running espionage operations on its territory, both before and after the war they fought in 2008.

The ministry said the four had been arrested for passing information "obtained because of their work to an organisation acting undercover for the intelligence services of a foreign country, against the interests of Georgia".

"Very serious charges will be put forward," Deputy Interior Minister Eka Zguladze told AFP, saying that the investigation was continuing.

The four suspects include Saakashvili's photographer Irakli Gedenidze, whose pictures of the Georgian leader are often printed in the international media.

"I am convinced that my son is not a traitor," Gedenidze's mother Marika told Georgian TV channel Rustavi-2.

European Pressphoto Agency photographer Zurab Kurtsikidze, foreign ministry press centre photographer Giorgi Abdaladze, and Gedenidze's wife, local newspaper photographer Natia Gedenidze, are the others who were held.

A photographer working for the Associated Press was also detained but later released without charge after being questioned.

Lawyers for some of the accused told local media that the case had been classified as "secret" because it concerns national security issues, potentially restricting information about further developments.

Police have not yet said what information was allegedly passed to the foreign power.

Officers seized computers and other equipment when they raided the suspects' homes overnight, relatives said.

"They searched all the rooms, took the computers, my father's laptop and child's computer, also all cellphones of the family members, all compact discs," Abdaladze's wife Nestan Neidze told the InterPressNews agency.

The European Pressphoto Agency which employed another of the accused, Zurab Kurtsikidze, called on the authorities to "correct this misunderstanding".

"Zurab always worked in strict respect of journalistic ethics andwithin the framework authorised by Georgian authorities," the agency's editor-in-chief Cengiz Seren said in a statement.

A small group of protesters gathered outside the interior ministry building where the photographers were being held, one of them holding a poster comparing Saakashvili to Belarus's strongman leader Alexander Lukashenko, who has repeatedly detained journalists.

Publicity-conscious Saakashvili, who says that his former Soviet republic is embracing European-style democracy, has always denied allegations from rights organisations that his government tries to control or pressurise the media.

Campaign group Reporters Without Borders however expressed concern about the arrests and their potential impact on press freedom.

"It is really disquieting that some of the most prominent photojournalists in Georgia are accused of spying," said Johann Bihr of Reporters Without Borders.

The Russian foreign ministry said that the allegations were typical of the Saakashvili administration.

"This points to the level of democracy in Georgia, which has often been remarked upon by international organisations recently," Russian foreign ministry spokesman Alexander Lukashevich told a news conference.

The arrests came a day after nine people including four Russian citizens were sentenced to jail terms ranging from 11 to 14 years for alleged involvement in a major Moscow-backed espionage network in Georgia.

Officials said the spy ring had provided secret information on the country's armed forces to the Russian military foreign intelligence service, the GRU.

They said that the network had been cracked in an operation that saw Georgian security services recruiting a double agent within the GRU.

Tensions between Georgia and Russia have remained high since the 2008 war, with Tbilisi also accusing Moscow of organising a series of bomb blasts on targets including the US embassy last year.

Moscow has dismissed the claims, accusing the Saakashvili administration of being anti-Russian.