Tehran is considering a replacement for the Russian S-300 missile defense system, a senior Iranian lawmaker told Fars news agency Monday.

Russia signed a contract with Iran in 2007 to deliver five S-300 advanced ground-to-air missiles — which can target aircraft or guided missiles — at a cost of $800 million.

In 2010, Russia’s then-president Dmitry Medvedev cancelled the contract because of UN sanctions and strong US and Israeli pressure over concerns about Tehran’s disputed nuclear program. […]