BRUSSELS, June 25 -- The North Atlantic Treaty Organization (NATO) would keep its door open to new members, NATO Secretary-General Anders Fogh Rasmussen said here Wednesday.

Rasmussen, who was attending NATO's foreign affairs ministers' meeting, said the ministers reached an agreement on the Western military bloc's enlargement during the first day of talks Tuesday.

"Let me be clear: NATO's door remains open and no third country has a veto over NATO enlargement," he said.

According to NATO's website, the ministers reviewed the progress made by the four aspirant countries -- Georgia, Montenegro, Bosnia and Herzegovina, and the former Yugoslav republic of Macedonia -- over dinner Tuesday.

The NATO chief said there was an agreement in principle by allies to develop a substantive package for Georgia that would help it come closer to NATO. Elements of the package would be worked out in the coming weeks.

On Montenegro, NATO will open intensified and focused talks and assess by the end of 2015 at the latest whether to invite that country to join.

"Each one has work to do, in different areas and we will give aspirants the support they need to get them through the door," Rasmussen said.

On Wednesday, the ministers will mull measures to strengthen collective defense and review relations with Russia.

They are expected to agree on a package of long-term support measures for Ukraine, including the creation of new trust funds, according to the alliance's website.

The ministers will also focus on preparations for the Wales summit, which will be held in September.

Rasmussen said the Wales summit would "mark the success" of NATO's open door policy and maintain its momentum.