Iranian leaders are working to solidify ties with Afghanistan, Pakistan and Iraq in a move that highlights Iran’s goal of taking a lead role in the region, the Wall Street Journal reported on Monday.

At a meeting in Tehran last Friday, Iranian President Mahmoud Ahmadinejad spoke to the presidents of Afghanistan and Pakistan about “many issues … that might come up after the nato military force goes out of Afghanistan,” according to Iranian Foreign Minister Ali Akbar Salehi.

“The three presidents were very forthcoming in carrying out the cooperation and contacts so as to make sure things will go as smoothly as it could,” Salehi said in a comment that is seen as taking a jab at the United States, which is competing with Iran more and more for influence in the region, especially since January when populace uprisings began to sweep through the Middle East.

Western nations had urged countries not to attend the summit, which Iran called an “International Conference on the Global Fight against Terrorism.” But representatives from around 60 nations attended despite the lobbying of the U.S. and other Western nations.

Why is Tehran ramping up its overtures to these three key U.S. allies now? The timing coincides with the U.S. military’s withdrawal from the region.

On June 22, President Barack Obama announced U.S. plans to withdraw 33,000 troops from Afghanistan over the next 15 months. Previously, Washington announced that it will pull all of its remaining 45,000 troops out of Iraq by the end of 2011.

The U.S. is packing up, and Iran wants to fill any void it leaves behind.

Iran’s overtures to these three nations also come amid rising tensions between the U.S. and the three separate governments, each of which Washington has pumped billions of dollars of aid money into.

In a statement posted on the Iranian presidency’s website on Friday, Afghan President Hamid Karzai said, “The Afghan people want the departure of foreign forces, and therefore Iran and Pakistan can play an important role in establishing a durable peace in Afghanistan.”

A few days before that, Karzai celebrated President Obama’s announcement about the U.S. plans to withdraw troops from Afghanistan.

In Pakistan, a surge of anti-Americanism spawned by the U.S.’s killing of Osama bin Laden near Islamabad in May has placed Pakistani leaders under domestic pressure to reduce their U.S. ties.

In beleaguered Iraq, there is no shortage of voices blaming the continued presence of U.S. troops for the country’s instability and security issues.

For example, Saad al-Mutallebi, a member of the country’s State of Law coalition, called on Iraq last week to maintain its ties with neighboring nations, and not to permit Washington to persuade Baghdad that these countries are a threat to Iraq. Also Muqtada al-Sadr, an Iraqi Shiite cleric, has staked his reputation on driving U.S. troops out of the country.

With tensions on the rise between the U.S. and these three nations, Iran views it as a perfect time to pounce. Iran has been encouraging Afghanistan and Pakistan to sever their military ties with Washington, and used the summit in Tehran this weekend as an opportunity to play up its international clout.

Two of the overarching trends the Trumpet watches for and reports on are the decline of the U.S. and the rise of Iran-led radical Islamism. Both of these trends are seen in Iran’s wooing of U.S. allies away from Washington and toward Tehran. Expect Washington to continue to lose power in the Middle East as Iran’s sphere of influence expands.