European wheat futures were higher on Wednesday, supported by steady export demand, firm Black Sea prices and logistical problems caused by rail strikes in France.

Price moves were moderate as grain markets remained cautious before this Friday's widely followed US Department of Agriculture (USDA) global crop estimates and amid uncertainty over military tensions between the United States and Iran.

Benchmark March milling wheat on Paris-based Euronext was up 1.00 euro, or 0.5%, at 189.50 euros a tonne at 1724 GMT.

The contract was holding near last Thursday's six-month top of 190.75 euros that came after a year-end rally fuelled by an outline US-Chinese trade agreement.

An import tender held by Egypt on Wednesday underscored brisk overseas demand and a recent rise in Black Sea prices, although they were still cheaper than an offer of French wheat.

Results in the tender were pending.

In France, concern over logistical snags due to a month-old rail strike over pension reform at a time of brisk export demand kept wheat physical premiums firm in French port zones, brokers said.

"Export demand is there and some people have logistical problems with trains and are having to buy backup supplies," a grain broker said.

French soft wheat exports outside the European Union reached 1 million tonnes in November, the highest monthly volume since the start of the season in July, customs data on Wednesday showed.

The volume shipped outside the EU in December was estimated to have increased further to around 1.2 million tonnes, provisional port data compiled by Refinitiv showed.

In Germany, cash premiums in Hamburg were underpinned by a brisk export programme and talk that French logistical setbacks may divert loadings to other EU countries.

Standard bread wheat with 12% protein for January delivery in Hamburg was offered for sale unchanged at 5.0 euros over the Paris March contract.

Buyers were offering up to 4 euros over Paris.