A ship approaches supertanker Grace 1 off the coast of Gibraltar on July 6, 2019. (AFP photo)

TEHRAN, July 10 (Xinhua) -- Iranian President Hassan Rouhani on Wednesday warned Britain of the "consequences" of the recent seizure of an Iranian oil tanker in the Strait of Gibraltar, Press TV reported.

"I remind the Britons: you are the ones initiating insecurity, and you will come to realize its consequences in the future," Rouhani said in a cabinet meeting.

On July 4, British Royal Marines seized an Iranian ship heading to Syria in the Strait of Gibraltar on the ground that the ship is "in breach of EU sanctions," according to western media.

However, the Spanish acting foreign minister said the seizure of Grace 1 was at the U.S. request.

The British seizure of the tanker is "very juvenile, heinous, and wrongful" and "to their detriment," Rouhani said.

On Tuesday, Mohammad Hossein Baqeri, chief of staff of the Iranian Armed Forces, said Iran will respond to Britain's seizure of its oil tanker at the appropriate time and place.

Britain "seized the Iranian oil tanker Grace 1 in international waters on bogus charges," said Baqeri.

"This measure will not go unanswered," the Iranian commander warned.

Meanwhile, Mohsen Rezaei, secretary of Iran's Expediency Discernment Council, said Iran should seize a British oil vessel in case London refuses to release the Iranian oil tanker.

"If Britain does not release the Iranian oil tanker, it is the Iranian authorities' duty to make a reciprocal move and seize a British oil tanker," said Rezaei.