Pressure is mounting on German Chancellor Angela Merkel to tighten economic sanctions on Iran after news broke of a major gas deal between a German firm and the Islamic Republic.

The deal, reportedly worth some £78 million to German company Steiner-Prematechnik-Gastec, was criticised by Ms Merkel. But Germany's Federal Agency for Economics and Export Control had approved the project after considering it for a year, saying it did not violate any trade bans with Iran. Meanwhile, Iran has continued to threaten Israel verbally while refusing to give up its nuclear ambitions.

Groups such as the Anti-Defamation League and the Simon Wiesenthal Centre criticised the deal. Israel's ambassador to Berlin, Yoram Ben Zeev, reportedly asked Ms Merkel to order that the gas deal be rescinded, and the Israeli Foreign Ministry also expressed concerns.