TUNIS (Reuters) - Tunisian forces captured three large arms caches near the border with Libya over the weekend, including Kalashnikov rifles, rockets and landmines, the interior ministry said.

The caches in the border city of Ben Guerdane will stoke Tunisia's concerns about the threat of Islamist militants crossing over Libya, where pro-government forces are close to ending Islamic State's hold on Sirte city.

Islamic State, fighting to set up a Caliphate following its brand of Islam across North Africa and the Middle East, sent dozens of Islamic State fighters into Ben Guerdane in March, attacking army and police posts and killing at least 53 people.

Many of the militants in Libya are originally from Tunisia, and the country's young democracy since its 2011 uprising has been seen as a target for the hardline Islamist group.

Tunisia has increased security measures on the border with Libya to avoid the infiltration of hundreds of Islamic state fighters who may have fled from Sirte. European countries are also helping with training and technology to protect the border.

Two arms caches were discovered on Saturday and the third was found on Sunday, the ministry said.

(Reporting By Tarek Amara)