TEHRAN, (Reuters) – Iran launched a military manoeuvre near its border with Afghanistan on Saturday, the semi-official Fars news agency reported, days after naval exercises in the Gulf increased tensions with the West and pushed up oil prices.

Mohammad Pakpour, commander of the Revolutionary Guards’ ground forces, said the “Martyrs of Unity” exercises near Khvat, 60 km (40 miles) from Afghanistan, were “aimed at boosting security along the Iranian borders,” Fars reported.

The Revolutionary Guards’ naval forces’ 10-day exercise in the Gulf that ended last Monday worsened relations with Washington days after U.S. President Barack Obama approved sanctions that aim to stop countries buying Iranian oil.

Threats that Iran could close the Strait of Hormuz, which leads out of the Gulf and provides the outlet for most oil from the Middle East, pushed up oil prices and Iran warned Washington not to send an aircraft carrier back into the Gulf.

Forces with the USS John C. Stennis aircraft carrier strike group, the target of Tehran’s threat, rescued 13 Iranian fishermen from Somali pirates days after passing through the Strait.

Foreign Minister Ali Akbar Salehi played down the political significance of the rescue.

“On some occasions, Iran has helped and secured the released of many other countries’ sailors that had been caught by pirates,” he told state-run Press TV.

“This is a humanitarian gesture and it is not related to the countries’ relations with each other.”