Qatar on Sunday seized two Iranian boats carrying weapons, Kuwait's Al-Aan News reported.
Qatar is a member of the Peninsula Shield, the military arm of the Gulf Cooperation Council (GCC), which this month sent units to Bahrain in support of its Sunni-minority monarch.
The boats were held near Zubara in the northeast of Qatar where the territorial waters of Bahrain and Qatar converge, according to a source whom Al-Aan did not name.
The source did not give the number or nationality of those arrested on the boats, nor the final destination of the weapons.
Iran has been accused of fuelling tension in Shiite-majority Bahrain after its leaders issued statements supporting Shiite protesters in the tiny kingdom and harshly criticising the Bahraini government and the deployment of Peninsula Shield’s forces in Bahrain.
Tensions between the Sunni-ruled Arab Gulf nations and Shiite Iran have run high since popular revolutions started sweeping through the Arab world like a brush-fire earlier this year.