(Reuters) - Iran would take pre-emptive action against its enemies if it felt its national interests were endangered, the deputy head of the Islamic Republic´s armed forces was quoted by a semi-official news agency as saying on Tuesday.

"Our strategy now is that if we feel our enemies want to endanger Iran´s national interests, and want to decide to do that, we will act without waiting for their actions," Mohammad Hejazi told Fars news agency.

Iran is facing increasing international pressure and isolation over its disputed nuclear activity. Expanded Western sanctions aim to block its economically vital oil exports and Tehran has said it could retaliate by shutting the Strait of Hormuz shipping lane vital to global energy supplies.

Still, a top U.S. intelligence official said last week that while U.S. spy services believed Iran would respond if attacked, they thought it was unlikely to start a conflict.

Israel and the United States do not rule out military action against Iran if sanctions and diplomacy fail to rein in its nuclear energy campaign.

Senior U.N. inspectors have begun their second round of talks in Tehran in three weeks, seeking Iranian explanations with respect to intelligence about "possible military dimensions" to the Iranian nuclear program.

Iran denies Western accusations that it is covertly seeking the means to build nuclear weapons and in recent weeks has again vowed no nuclear retreat, but also voiced willingness to resume negotiations with world powers without preconditions.

Iran says it is enriching uranium solely as fuel for a future network of nuclear power stations, not for bombs.

The European Union enraged Tehran last month when it decided to slap a boycott on its oil to take full effect on July 1.

On Sunday, Iran´s oil ministry announced a retaliatory halt in oil sales to French and British companies, though that step will be largely symbolic as those firms had already greatly reduced purchases of Iranian crude.

On Monday, the European Commission said Belgium, the Czech Republic and the Netherlands had already stopped buying Iranian oil, while Greece, Spain and Italy were cutting back purchases.

Tighter sanctions including the pending embargo on Iranian oil imports into the EU have helped push oil prices up to $119 a barrel from $107 at the start of the year. (Editing by Mark Heinrich) (© Thomson Reuters 2012. 02/21/12)