Consider a liquid under the atmospheric pressure. Nonzero pressure inside the liquid means repulsion between molecules. On the other hand to explain the surface tension it is usually said that molecules attract each other!
Which one is correct: attraction or repulsion?
Liquid molecules which are too close to one another will repel one another and liquid molecules which are too far apart will attract one another.
The comparison has been made to the equilibrium separation of the liquid molecules when the net force on the liquid molecule is zero.
A liquid molecule in the body of a liquid has to support the weight of the liquid molecules above it.
To provide an upward force on that liquid molecule it gets closer than the equilibrium separation so that there is a net repulsive force on the liquid molecule due to its nearest neighbours.
The density of a liquid increases with depth but by very little.
At the surface the liquid molecules do not have nearest neighbours above them and so there is a net downward force due to the neighbours below the surface molecules.
To counteract that downward force the surface molecules have a greater than equilibrium separation which means that there is a net force of attraction between the surface molecules - this is the origin of the surface tensional force.
The sketch graph below illustrates the transition from repulsive to attractive as one goes through the equilibrium separation $r_0$.
So the answer is that both are correct and the actual force acting, attractive or repulsive, depends on the separation of the liquid molecules.
The classic picture for intermolecular forces looks something like this:
https://en.wikipedia.org/wiki/Lennard-Jones_potential#/media/File:12-6-Lennard-Jones-Potential.svg
Unless two molecules are very close to each other, the forces between them are generally attractive(In the photo above, for distances greater than $r_{m}$). This is due primarily to the Van der Waals force.
Molecules well inside the liquid, on average experience the Van der Waals attraction from all sides. Hence the net such force on such molecules is zero. But for molecules near the surface, there is an attraction only towards the bulk of the liquid. Hence, the liquid attempts to minimize it's surface area, and this is termed as surface tension.
Edit: When you talk about 'pressure', it is when the short range repulsion forces come into play when two molecules are very close to each other. For example, when a liquid molecule comes very close to molecules of the container, it rebounds. The same thing is happening for two molecules coming very close to each other either near the surface or within the bulk of the liquid. But the bulk attractive Van Der Waals forces have a more dominating effect for molecules near the surface, when compared with the repulsive 'bounces' with molecules near the surface.
