Kenya this week sentenced two Iranians convicted of plotting attacks against U.S. and Israeli targets while three Nigerian terrorist suspects allegedly trained in Iran are awaiting trial in the West African state on similar charges.

Increasingly, Africa seems to be emerging as a new front in the shadowy clandestine war between the Islamic Republic and its leading enemies.

A few weeks ago, British arms-trafficking investigators said they had found evidence that Tehran has been secretly shipping arms and ammunition to Nigeria, Kenya, Uganda, the Ivory Coast and South Sudan -- all African states plagued by conflict.

These shipments, made over several years, don't appear to be directly linked to terrorist plots in Africa, or anywhere else but they underline the scale of destabilizing covert operations in which Tehran's intelligence chiefs are engaged.

It also reflects Iran's increasing focus on developing its political and intelligence interests in Africa, in large part to counter Israel's advances across the continent in its quest for diplomatic -- and intelligence -- allies.

In recent months, Iranian operations, some involving agents of Lebanon's Hezbollah, Iran's powerful surrogate in the Levant, have been uncovered in India, Nepal, Thailand, Azerbaijan, Bulgaria, Cyprus and elsewhere, underlining Iran's global reach.

Many suspects were arrested and convicted. In all these countries, their targets were Israeli.

From May 2011 through July 2012, more than 20 attacks linked to Iran and Hezbollah against Israelis and Jews were thwarted.

Not all have been publicly reported because that could compromise counter-terror security operations.

This recent upsurge in terrorist plots against Israel indicates that Tehran, with Hezbollah's help, is seeking to step up its operations following the assassination of its nuclear scientists as part of a U.S.-Israeli campaign to cripple Iran's contentious nuclear program.

The apparent shift to Africa suggests that countries there are considered less risky, for now anyway, than Europe or Asia, which have been used by Tehran's hit squads over the last two or three years.

On Monday, a Nairobi court sentenced two Iranians, suspected of belonging to the Revolutionary Guards' crack al-Quds Force, to life in prison for plotting terrorist attacks against Western and Israeli targets.

When they were arrested in June 2012 they led security authorities to 33 pounds of military-grade RDX explosives. But officials said another 185 pounds of RDX hasn't been recovered.

In the Nigerian case, the accused are all Nigerian nationals arrested in December. They were allegedly taken to Iran for training.

Ely Karmon of the Institute for Counterterrorism outside Tel Aviv said Tehran has been establishing sleeper cells across Africa since the 1990s.

"This isn't surprising," he told The Jerusalem Post. "We saw that in Kenya last year."

Five Israelis were killed in a bus bombing in the Bulgarian resort of Burgas July 18, 2012, an attack attributed to Hezbollah.

It may have been a suicide attack because the bomber was also killed. But Hezbollah, which pioneered suicide bombings against Israeli forces in Lebanon in the 1980s, isn't known to have carried out a suicide operation for many years.

Two accomplices, identified as Lebanese Hezbollah agents holding Canadian and Australian passports, escaped and are believed to be holed up in Beirut under Hezbollah protection.

In Cyprus, a self-confessed Hezbollah operative, who carried a Swedish passport and admitted gathering intelligence on Israeli tourists on the Mediterranean island, was imprisoned for four years March 29 for plotting terrorist attacks against Israelis.

Hezbollah long claimed its operations were restricted to the Middle East, although the United States alleges the Lebanese organization was involved in two bombings in Buenos Aires in 1992 and 1994 that killed about 110 people.

In 2006, international arrest warrants for the bombings were issued for several Iranian and Hezbollah figures.

They included Hezbollah's iconic military mastermind, Imad Mughniyeh, and Iran's top leaders of the time, including former President Ali Akbar Hashemi Rafsanjani, intelligence chief Ali Fallahijan and Ahmad Vahidi, who's currently defense minister.

Mughniyeh, hunted by the Americans since 1983, was assassinated Feb. 12, 2008, in a bombing in Damascus, Syria.

Israel was blamed, although it has never acknowledged responsibility for killing Mughniyeh, who until Osama bin Laden came along was the world's most wanted fugitive.

Hezbollah chief Hassan Nasrallah declared global war against Israel and vowed revenge. Ever since, Israel has braced for trouble.