Tunis (AFP) - Tunisia on Thursday accused Turkey of facilitating the transit of fighters bound for neighbouring Syria and Iraq, where thousands of its citizens have joined the ranks of jihadist groups.

The accusation by Foreign Minister Taieb Baccouche comes just two weeks after the Islamic State group claimed responsibility for a deadly attack on tourists at the Bardo National Museum.

Tunisia says 3,000 of its citizens are fighting alongside jihadist groups in Syria, Iraq and Libya, and that 500 battle-hardened veterans have returned to the country where they are considered a security threat.

"We have asked our ambassador in Turkey to draw the attention of the Turkish authorities to the fact that we do not want a Muslim nation such as Turkey to help directly or indirectly terrorism in Libya by facilitating the movements of terrorists," Baccouche said.

He said Turkey was a "passage point" for fighters who go to Syria or for those who travel to Libya and then infiltrate across the porous border into Tunisia.

Tunisia has said that the two gunmen who had killed 22 foreign tourists and a policeman at the Bardo on March 18 had trained on the use of weapons in Libya, where IS has gained a foothold in recent months.

The two assailants were themselves gunned down, and on Sunday Tunisia said it had killed the alleged leader of the jihadists behind the massacre, Algerian Lokmane Abou Sakhr.

Turkey has been repeatedly criticised by its Western allies for not doing enough to halt the flow across Turkish territory of European nationals seeking to join IS jihadists in Syria.

Ankara has reported a number of arrests in recent months and insists it is doing all it can to control the border.