A high-ranking delegation from the Royal Dutch Shell company will meet Iranian Oil Minister Bijan Namdar Zanganeh in Tehran on Sunday to discuss energy cooperation.

The Iranian oil minister and the Shell delegation will negotiate a wide range of issues in oil, gas and petrochemical fields.

In addition to investments in Iran's energy sector, the Royal Dutch Shell has negotiated with Iran to implement major projects, including construction of liquefied natural gas (LNG) plants and producing oil products from natural gas, but the projects have not yet been concluded due to their high costs.

Shell was reportedly blocked earlier this year from settling a $2.3bln debt with Iran through the supply of grain and medicine.

In 1999, Shell defied a US sanctions threat to sign an estimated $800mln (£492mln) deal with Iran to develop two offshore oil fields in the Persian Gulf known as Soroosh and Nowrooz.

In April, the Shell company expressed its willingness to resume operations in Iran.

"We have had some talks with Shell company officials for their return to Iran's oil products market," Managing Director of Pars Oil Company Hassan Vafayee told reporters on the sidelines of the 20th International Oil Exhibition in Tehran.

He underlined that many foreign companies are waiting for the removal of the western sanctions imposed against Tehran to return to the Iranian market.

Before the tightening of sanctions against Iran a few years ago, Shell and Total were two of the most active companies doing business with Tehran.