Bahrain on Monday accused Qatar of seizing 15 boats from the kingdom with 20 fishermen on board, in the latest spat between the neighbours caught up in a diplomatic dispute.

In a statement on its website, Bahrain's interior ministry said Qatar had seized three Bahraini boats with 16 aboard in the past two days.

Coast Guard commander Ala Siyadi said in the statement that this took to 15 the overall number of boats seized and 20 the number of fishermen.

The Bahraini authorities did not specify when the other four people were detained, but the ministry said some boats had been seized in 2009.

Bahrain joined a Saudi-led bloc of nations in breaking diplomatic ties with Qatar on June 5, accusing it of links to extremists and getting close to Iran.

The gas-rich emirate flatly rejects the allegations and the diplomatic row, the worst seen in the Gulf for decades, shows no signs of abating.