(Reuters) - Iran has signed a flurry of deals with foreign companies since the easing of international sanctions on Tehran in 2016 after it agreed to limits on its disputed nuclear programme.

People are reflected in window as they walk on a sidewalk in Tehran, Iran October 14, 2017. Nazanin Tabatabaee Yazdi/TIMA via REUTERS

But U.S.-Iranian tensions are rising again after President Donald Trump unveiled a more confrontational U.S. policy towards Tehran, including an announcement that he will decertify the 2015 nuclear deal reached under his predecessor Barack Obama.

That would open a 60-day window in which the U.S. Congress could re-impose sanctions, which could undo the agreement.

Trump’s announcement could heighten caution among many Western and Asian companies that are planning to, or considering whether to, invest in the Iranian economy.

The Islamic Republic needs foreign investment for repairs and upgrades of oil and gas fields that deteriorated during a decade of isolation, and is also seeking new technology for its oil industry.

Below is a list of deals and memoranda of understanding (MoU) Iran has signed over the past year.

OIL AND GAS

* France’s Total became in November 2016 the first oil major to sign a big deal with Tehran since the country was re-admitted to international trade markets, and agreed to help it develop the world’s largest gas field, South Pars.

* Shell signed a provisional deal in December to develop Iranian oil and gas fields South Azadegan, Yadavaran and Kish. But Chief Executive Ben van Beurden said Shell had no near-term investment opportunities in Iran.

* Iran has named 29 companies from more than a dozen countries as being allowed to bid for oil and gas projects using a new, less restrictive contract model.

The firms include Shell, Total, Italy’s Eni, Malaysia’s Petronas and Russia’s Gazprom and Lukoil, as well as companies from China, Austria, Japan and other countries.

However, Iran’s first tender since the lifting of sanctions for developing its largest oilfield, Azadegan, has been postponed several times for unspecified reasons, and is not expected to take place in 2017.

* Russia’s Zarubezhneft signed a MoU for a feasibility study on two joint fields in the west of Iran.

* Norway’s Aker Solutions signed an MoU to modernise the Iranian oil industry.

* Austria’s OMV signed a MoU in May for projects in the Zagros area of western Iran and the Fars field in the south.

* South Korea’s Daewoo Engineering and Construction (Daewoo E&C) signed an MoU to carry out construction of an oil refinery in Bandar Jask on the southern coast of Iran.

* Italy’s Saipem signed MoUs to cooperate on pipeline projects, upgrading of refineries and development of the Tous gas field in the northeastern province of Khorasan Razavi.

* Norwegian oil and gas company DNO said it was the second western energy company after Total to sign a deal with Iran under which it agreed to study the development of the Changuleh oilfield in western Iran.

* Lukoil, Russia’s second biggest oil producer, hopes to reach a decision on developing two new oilfields in Iran.

* BASF’s Wintershall oil and gas exploration subsidiary signed a MoU with the National Iranian Oil Company in April 2016. In February this year, it said it was in talks with Iran about a possible investment of its oil and gas division in the country but no decision was on the cards because of uncertainty over the status of economic sanctions.

AVIATION

* Iran has set out plans to renew its ageing fleet and invest in airport infrastructure to meet expectations of sharp growth in its under-served aviation market post-sanctions.

* Flag carrier IranAir has ordered 100 aircraft from Airbus and taken delivery of three.

* Boeing has a deal to sell 80 aircraft to IranAir.

* Airbus and Boeing have received U.S. export licences to cover part of the deals, but bankers say doubts remain over the availability of financing because of fears of further sanctions.

* European turboprop maker ATR, half-owned by Airbus and Leonardo, sold 20 aircraft to IranAir, which has so far taken six to serve regional cities.

* Aseman Airlines has agreed to buy 30 Boeing 737 MAX jets in Iran’s first new business with the U.S. planemaker since Trump took office.

* Domestic carrier Zagros Airlines signed a MoU in June to buy 20 Airbus A320neo and eight A330neo aircraft.

* Privatised Iran Airtour signed in June a MoU for 45 Airbus A320neos.

RAILWAYS

* China National Machinery Import and Export Corporation, signed a 2.2 billion-euro ($2.60 billion) deal in May with Iran’s MAPNA for electrification of a high-speed rail line between Tehran and Mashhad.

* Iran’s state rail company and its Italian counterpart, Ferrovie dello Stato (FS) signed a final agreement worth 1.2 billion euros ($1.37 billion) in July to build a high-speed railway between the cities of Qom and Arak.

* French train maker and manufacturing group Alstom signed a deal in July for a joint venture that will build metro and suburban rail carriages in Iran.

* Germany’s Siemens signed a contract in October 2016 to upgrade Iran’s railway network. Siemens will also supply components for 50 diesel-electric locomotives to Iran.

AUTOMOTIVE

* French carmakers PSA and Renault have moved swiftly to sign new production deals to upgrade their pre-sanctions partnerships with Iran Khodro and SAIPA.

PSA has signed production deals worth 700 million euros ($768 million), while Renault has announced a new plant investment to increase its production capacity to 350,000 vehicles a year.

The resumption of official sales in Iran helped PSA more than triple its Middle East and Africa deliveries in the first half of the year.

* Volkswagen said in July it would start exporting cars to Iran, returning to the resurgent market after more than 17 years.

* Trump’s stance against Iran has deepened the caution of German carmakers with large American exposures. BMW are among those that have put Iranian ambitions on hold.

However, Germany’s Mercedes-Benz Trucks signed a contract with Iran Khodro in September, laying the foundation for resuming distribution of its trucks in Iran.

BANKING

* Oberbank signed a deal with Iran in September, enabling it to finance new ventures there and making it one of the first European banks to do so since sanctions were eased.

However, major global banks have so far shied away from handling Iranian-related business, citing the risk of violating ongoing U.S. sanctions. Among them is HSBC, which has said it has no intention of doing any new business involving Iran.

($1 = 0.8459 euros)